diff --git a/camera/ICameraServiceProxy.cpp b/camera/ICameraServiceProxy.cpp
index 06a5afb..694e9c3 100644
--- a/camera/ICameraServiceProxy.cpp
+++ b/camera/ICameraServiceProxy.cpp
@@ -29,11 +29,21 @@
     BpCameraServiceProxy(const sp<IBinder>& impl) : BpInterface<ICameraServiceProxy>(impl) {}
 
     virtual void pingForUserUpdate() {
-        Parcel data, reply;
+        Parcel data;
         data.writeInterfaceToken(ICameraServiceProxy::getInterfaceDescriptor());
-        remote()->transact(BnCameraServiceProxy::PING_FOR_USER_UPDATE, data, &reply,
+        remote()->transact(BnCameraServiceProxy::PING_FOR_USER_UPDATE, data, nullptr,
                 IBinder::FLAG_ONEWAY);
     }
+
+    virtual void notifyCameraState(String16 cameraId, CameraState newCameraState) {
+        Parcel data;
+        data.writeInterfaceToken(ICameraServiceProxy::getInterfaceDescriptor());
+        data.writeString16(cameraId);
+        data.writeInt32(newCameraState);
+        remote()->transact(BnCameraServiceProxy::NOTIFY_CAMERA_STATE, data, nullptr,
+                IBinder::FLAG_ONEWAY);
+    }
+
 };
 
 
@@ -47,9 +57,16 @@
             pingForUserUpdate();
             return NO_ERROR;
         } break;
+        case NOTIFY_CAMERA_STATE: {
+            CHECK_INTERFACE(ICameraServiceProxy, data, reply);
+            String16 cameraId = data.readString16();
+            CameraState newCameraState =
+                static_cast<CameraState>(data.readInt32());
+            notifyCameraState(cameraId, newCameraState);
+            return NO_ERROR;
+        } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
 }
 }; // namespace android
-
diff --git a/camera/camera2/ICameraDeviceUser.cpp b/camera/camera2/ICameraDeviceUser.cpp
index d2dc200..2a9fd2b 100644
--- a/camera/camera2/ICameraDeviceUser.cpp
+++ b/camera/camera2/ICameraDeviceUser.cpp
@@ -49,7 +49,8 @@
     WAIT_UNTIL_IDLE,
     FLUSH,
     PREPARE,
-    TEAR_DOWN
+    TEAR_DOWN,
+    PREPARE2
 };
 
 namespace {
@@ -366,6 +367,21 @@
         return reply.readInt32();
     }
 
+    virtual status_t prepare2(int maxCount, int streamId)
+    {
+        ALOGV("prepare2");
+        Parcel data, reply;
+
+        data.writeInterfaceToken(ICameraDeviceUser::getInterfaceDescriptor());
+        data.writeInt32(maxCount);
+        data.writeInt32(streamId);
+
+        remote()->transact(PREPARE2, data, &reply);
+
+        reply.readExceptionCode();
+        return reply.readInt32();
+    }
+
     virtual status_t tearDown(int streamId)
     {
         ALOGV("tearDown");
@@ -592,7 +608,14 @@
             reply->writeInt32(tearDown(streamId));
             return NO_ERROR;
         } break;
-
+        case PREPARE2: {
+            CHECK_INTERFACE(ICameraDeviceUser, data, reply);
+            int maxCount = data.readInt32();
+            int streamId = data.readInt32();
+            reply->writeNoException();
+            reply->writeInt32(prepare2(maxCount, streamId));
+            return NO_ERROR;
+        } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
diff --git a/include/camera/ICameraServiceProxy.h b/include/camera/ICameraServiceProxy.h
index 12a555f..2613c01 100644
--- a/include/camera/ICameraServiceProxy.h
+++ b/include/camera/ICameraServiceProxy.h
@@ -23,15 +23,30 @@
 
 namespace android {
 
+/**
+ * Interface from native camera service to managed-side camera service proxy.
+ *
+ * Keep in sync with frameworks/base/core/java/android/hardware/ICameraServiceProxy.aidl
+ *
+ */
 class ICameraServiceProxy : public IInterface {
 public:
     enum {
         PING_FOR_USER_UPDATE = IBinder::FIRST_CALL_TRANSACTION,
+        NOTIFY_CAMERA_STATE
+    };
+
+    enum CameraState {
+        CAMERA_STATE_OPEN,
+        CAMERA_STATE_ACTIVE,
+        CAMERA_STATE_IDLE,
+        CAMERA_STATE_CLOSED
     };
 
     DECLARE_META_INTERFACE(CameraServiceProxy);
 
     virtual void pingForUserUpdate() = 0;
+    virtual void notifyCameraState(String16 cameraId, CameraState newCameraState) = 0;
 };
 
 class BnCameraServiceProxy: public BnInterface<ICameraServiceProxy>
@@ -48,5 +63,3 @@
 }; // namespace android
 
 #endif // ANDROID_HARDWARE_ICAMERASERVICEPROXY_H
-
-
diff --git a/include/camera/camera2/ICameraDeviceUser.h b/include/camera/camera2/ICameraDeviceUser.h
index a7bf8ab..4d8eb53 100644
--- a/include/camera/camera2/ICameraDeviceUser.h
+++ b/include/camera/camera2/ICameraDeviceUser.h
@@ -140,6 +140,11 @@
     virtual status_t        prepare(int streamId) = 0;
 
     /**
+     * Preallocate up to maxCount buffers for a given output stream asynchronously.
+     */
+    virtual status_t        prepare2(int maxCount, int streamId) = 0;
+
+    /**
      * Free all unused buffers for a given output stream.
      */
     virtual status_t        tearDown(int streamId) = 0;
diff --git a/media/img_utils/include/img_utils/DngUtils.h b/media/img_utils/include/img_utils/DngUtils.h
index 3dcedc5..1d8df9c 100644
--- a/media/img_utils/include/img_utils/DngUtils.h
+++ b/media/img_utils/include/img_utils/DngUtils.h
@@ -138,6 +138,34 @@
                                             double opticalCenterY,
                                             const double* kCoeffs);
 
+
+        /**
+         * Add FixBadPixelsList opcode for the given metadata parameters.
+         *
+         * Returns OK on success, or a negative error code.
+         */
+        virtual status_t addBadPixelListForMetadata(const uint32_t* hotPixels,
+                                                    uint32_t xyPairCount,
+                                                    uint32_t colorFilterArrangement);
+
+        /**
+         * Add FixBadPixelsList opcode.
+         *
+         * bayerPhase - 0=top-left of image is red, 1=top-left of image is green pixel in red row,
+         *              2=top-left of image is green pixel in blue row, 3=top-left of image is
+         *              blue.
+         * badPointCount - number of (x,y) pairs of bad pixels are given in badPointRowColPairs.
+         * badRectCount - number of (top, left, bottom, right) tuples are given in
+         *              badRectTopLeftBottomRightTuples
+         *
+         * Returns OK on success, or a negative error code.
+         */
+        virtual status_t addBadPixelList(uint32_t bayerPhase,
+                                         uint32_t badPointCount,
+                                         uint32_t badRectCount,
+                                         const uint32_t* badPointRowColPairs,
+                                         const uint32_t* badRectTopLeftBottomRightTuples);
+
         // TODO: Add other Opcode methods
     protected:
         static const uint32_t FLAG_OPTIONAL = 0x1u;
@@ -146,6 +174,7 @@
         // Opcode IDs
         enum {
             WARP_RECTILINEAR_ID = 1,
+            FIX_BAD_PIXELS_LIST = 5,
             GAIN_MAP_ID = 9,
         };
 
@@ -161,6 +190,8 @@
         ByteArrayOutput mOpList;
         EndianOutput mEndianOut;
 
+        status_t addOpcodePreamble(uint32_t opcodeId);
+
 };
 
 } /*namespace img_utils*/
diff --git a/media/img_utils/src/DngUtils.cpp b/media/img_utils/src/DngUtils.cpp
index b213403..9473dce 100644
--- a/media/img_utils/src/DngUtils.cpp
+++ b/media/img_utils/src/DngUtils.cpp
@@ -224,13 +224,7 @@
                                        uint32_t mapPlanes,
                                        const float* mapGains) {
 
-    uint32_t opcodeId = GAIN_MAP_ID;
-
-    status_t err = mEndianOut.write(&opcodeId, 0, 1);
-    if (err != OK) return err;
-
-    uint8_t version[] = {1, 3, 0, 0};
-    err = mEndianOut.write(version, 0, NELEMS(version));
+    status_t err = addOpcodePreamble(GAIN_MAP_ID);
     if (err != OK) return err;
 
     // Allow this opcode to be skipped if not supported
@@ -334,13 +328,7 @@
                                                double opticalCenterY,
                                                const double* kCoeffs) {
 
-    uint32_t opcodeId = WARP_RECTILINEAR_ID;
-
-    status_t err = mEndianOut.write(&opcodeId, 0, 1);
-    if (err != OK) return err;
-
-    uint8_t version[] = {1, 3, 0, 0};
-    err = mEndianOut.write(version, 0, NELEMS(version));
+    status_t err = addOpcodePreamble(WARP_RECTILINEAR_ID);
     if (err != OK) return err;
 
     // Allow this opcode to be skipped if not supported
@@ -373,5 +361,74 @@
     return OK;
 }
 
+status_t OpcodeListBuilder::addBadPixelListForMetadata(const uint32_t* hotPixels,
+                                                       uint32_t xyPairCount,
+                                                       uint32_t colorFilterArrangement) {
+    if (colorFilterArrangement > 3) {
+        ALOGE("%s:  Unknown color filter arrangement %" PRIu32, __FUNCTION__,
+                colorFilterArrangement);
+        return BAD_VALUE;
+    }
+
+    return addBadPixelList(colorFilterArrangement, xyPairCount, 0, hotPixels, nullptr);
+}
+
+status_t OpcodeListBuilder::addBadPixelList(uint32_t bayerPhase,
+                                            uint32_t badPointCount,
+                                            uint32_t badRectCount,
+                                            const uint32_t* badPointRowColPairs,
+                                            const uint32_t* badRectTopLeftBottomRightTuples) {
+
+    status_t err = addOpcodePreamble(FIX_BAD_PIXELS_LIST);
+    if (err != OK) return err;
+
+    // Allow this opcode to be skipped if not supported
+    uint32_t flags = FLAG_OPTIONAL;
+
+    err = mEndianOut.write(&flags, 0, 1);
+    if (err != OK) return err;
+
+    const uint32_t NUM_NON_VARLEN_FIELDS = 3;
+    const uint32_t SIZE_OF_POINT = 2;
+    const uint32_t SIZE_OF_RECT = 4;
+
+    uint32_t totalSize =  (NUM_NON_VARLEN_FIELDS  + badPointCount * SIZE_OF_POINT +
+            badRectCount * SIZE_OF_RECT) * sizeof(uint32_t);
+    err = mEndianOut.write(&totalSize, 0, 1);
+    if (err != OK) return err;
+
+    err = mEndianOut.write(&bayerPhase, 0, 1);
+    if (err != OK) return err;
+
+    err = mEndianOut.write(&badPointCount, 0, 1);
+    if (err != OK) return err;
+
+    err = mEndianOut.write(&badRectCount, 0, 1);
+    if (err != OK) return err;
+
+    if (badPointCount > 0) {
+        err = mEndianOut.write(badPointRowColPairs, 0, SIZE_OF_POINT * badPointCount);
+        if (err != OK) return err;
+    }
+
+    if (badRectCount > 0) {
+        err = mEndianOut.write(badRectTopLeftBottomRightTuples, 0, SIZE_OF_RECT * badRectCount);
+        if (err != OK) return err;
+    }
+
+    mCount++;
+    return OK;
+}
+
+status_t OpcodeListBuilder::addOpcodePreamble(uint32_t opcodeId) {
+    status_t err = mEndianOut.write(&opcodeId, 0, 1);
+    if (err != OK) return err;
+
+    uint8_t version[] = {1, 3, 0, 0};
+    err = mEndianOut.write(version, 0, NELEMS(version));
+    if (err != OK) return err;
+    return OK;
+}
+
 } /*namespace img_utils*/
 } /*namespace android*/
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 56521a2..bcfd83a 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1734,7 +1734,7 @@
     t->setVolume(mLeftVolume, mRightVolume);
 
     mSampleRateHz = sampleRate;
-    mFlags = t->getFlags(); // we suggest the flags above, but new AudioTrack() may not grant it.
+    mFlags = flags;
     mMsecsPerFrame = 1E3f / (mPlaybackRate.mSpeed * sampleRate);
     mFrameSize = t->frameSize();
     uint32_t pos;
@@ -1746,7 +1746,7 @@
     status_t res = NO_ERROR;
     // Note some output devices may give us a direct track even though we don't specify it.
     // Example: Line application b/17459982.
-    if ((mFlags & (AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD | AUDIO_OUTPUT_FLAG_DIRECT)) == 0) {
+    if ((t->getFlags() & (AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD | AUDIO_OUTPUT_FLAG_DIRECT)) == 0) {
         res = t->setPlaybackRate(mPlaybackRate);
         if (res == NO_ERROR) {
             t->setAuxEffectSendLevel(mSendLevel);
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
index 04a46f4..0ac29a8 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
@@ -877,6 +877,8 @@
                 ALOGV("AudioSink write would block when writing %zu bytes", copy);
             } else {
                 ALOGE("AudioSink write error(%zd) when writing %zu bytes", written, copy);
+                // This can only happen when AudioSink was opened with doNotReconnect flag set to
+                // true, in which case the NuPlayer will handle the reconnect.
                 notifyAudioTearDown();
             }
             break;
@@ -943,6 +945,10 @@
 int64_t NuPlayer::Renderer::getDurationUsIfPlayedAtSampleRate(uint32_t numFrames) {
     int32_t sampleRate = offloadingAudio() ?
             mCurrentOffloadInfo.sample_rate : mCurrentPcmInfo.mSampleRate;
+    if (sampleRate == 0) {
+        ALOGE("sampleRate is 0 in %s mode", offloadingAudio() ? "offload" : "non-offload");
+        return 0;
+    }
     // TODO: remove the (int32_t) casting below as it may overflow at 12.4 hours.
     return (int64_t)((int32_t)numFrames * 1000000LL / sampleRate);
 }
@@ -1764,6 +1770,12 @@
         const uint32_t frameCount =
                 (unsigned long long)sampleRate * getAudioSinkPcmMsSetting() / 1000;
 
+        // The doNotReconnect means AudioSink will signal back and let NuPlayer to re-construct
+        // AudioSink. We don't want this when there's video because it will cause a video seek to
+        // the previous I frame. But we do want this when there's only audio because it will give
+        // NuPlayer a chance to switch from non-offload mode to offload mode.
+        // So we only set doNotReconnect when there's no video.
+        const bool doNotReconnect = !hasVideo;
         status_t err = mAudioSink->open(
                     sampleRate,
                     numChannels,
@@ -1774,13 +1786,14 @@
                     mUseAudioCallback ? this : NULL,
                     (audio_output_flags_t)pcmFlags,
                     NULL,
-                    true /* doNotReconnect */,
+                    doNotReconnect,
                     frameCount);
         if (err == OK) {
             err = mAudioSink->setPlaybackRate(mPlaybackSettings);
         }
         if (err != OK) {
             ALOGW("openAudioSink: non offloaded open failed status: %d", err);
+            mAudioSink->close();
             mCurrentPcmInfo = AUDIO_PCMINFO_INITIALIZER;
             return err;
         }
diff --git a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
index 58ff113..af0351e 100644
--- a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
+++ b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
@@ -134,7 +134,9 @@
             return;
         }
     }
-    mHandler->pause();
+    if (mHandler != NULL) {
+        mHandler->pause();
+    }
 }
 
 void NuPlayer::RTSPSource::resume() {
diff --git a/media/libstagefright/AudioSource.cpp b/media/libstagefright/AudioSource.cpp
index 3505844..6e4a1dd 100644
--- a/media/libstagefright/AudioSource.cpp
+++ b/media/libstagefright/AudioSource.cpp
@@ -290,6 +290,10 @@
 
 status_t AudioSource::dataCallback(const AudioRecord::Buffer& audioBuffer) {
     int64_t timeUs = systemTime() / 1000ll;
+    // Estimate the real sampling time of the 1st sample in this buffer
+    // from AudioRecord's latency. (Apply this adjustment first so that
+    // the start time logic is not affected.)
+    timeUs -= mRecord->latency() * 1000LL;
 
     ALOGV("dataCallbackTimestamp: %" PRId64 " us", timeUs);
     Mutex::Autolock autoLock(mLock);
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index e7f6864..b1d7b13 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -1066,7 +1066,7 @@
     *delayMs = 0;
     if (stream == AUDIO_STREAM_TTS) {
         ALOGV("\t found BEACON stream");
-        if (mOutputs.isAnyOutputActive(AUDIO_STREAM_TTS /*streamToIgnore*/)) {
+        if (!mTtsOutputAvailable && mOutputs.isAnyOutputActive(AUDIO_STREAM_TTS /*streamToIgnore*/)) {
             return INVALID_OPERATION;
         } else {
             beaconMuteLatency = handleEventForBeacon(STARTING_BEACON);
@@ -2000,6 +2000,9 @@
     snprintf(buffer, SIZE, " Force use for hdmi system audio %d\n",
             mEngine->getForceUse(AUDIO_POLICY_FORCE_FOR_HDMI_SYSTEM_AUDIO));
     result.append(buffer);
+    snprintf(buffer, SIZE, " TTS output %s\n", mTtsOutputAvailable ? "available" : "not available");
+    result.append(buffer);
+
     write(fd, result.string(), result.size());
 
     mAvailableOutputDevices.dump(fd, String8("output"));
@@ -2680,7 +2683,8 @@
     mAudioPortGeneration(1),
     mBeaconMuteRefCount(0),
     mBeaconPlayingRefCount(0),
-    mBeaconMuted(false)
+    mBeaconMuted(false),
+    mTtsOutputAvailable(false)
 {
     audio_policy::EngineInstance *engineInstance = audio_policy::EngineInstance::getInstance();
     if (!engineInstance) {
@@ -2737,6 +2741,9 @@
                 ALOGW("Output profile contains no device on module %s", mHwModules[i]->mName);
                 continue;
             }
+            if ((outProfile->mFlags & AUDIO_OUTPUT_FLAG_TTS) != 0) {
+                mTtsOutputAvailable = true;
+            }
 
             if ((outProfile->mFlags & AUDIO_OUTPUT_FLAG_DIRECT) != 0) {
                 continue;
@@ -4036,6 +4043,12 @@
 }
 
 uint32_t AudioPolicyManager::handleEventForBeacon(int event) {
+
+    // skip beacon mute management if a dedicated TTS output is available
+    if (mTtsOutputAvailable) {
+        return 0;
+    }
+
     switch(event) {
     case STARTING_OUTPUT:
         mBeaconMuteRefCount++;
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.h b/services/audiopolicy/managerdefault/AudioPolicyManager.h
index bf3ae4a..bbdf396 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.h
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.h
@@ -548,6 +548,7 @@
         uint32_t mBeaconMuteRefCount;   // ref count for stream that would mute beacon
         uint32_t mBeaconPlayingRefCount;// ref count for the playing beacon streams
         bool mBeaconMuted;              // has STREAM_TTS been muted
+        bool mTtsOutputAvailable;       // true if a dedicated output for TTS stream is available
 
         AudioPolicyMixCollection mPolicyMixes; // list of registered mixes
 
diff --git a/services/camera/libcameraservice/CameraService.cpp b/services/camera/libcameraservice/CameraService.cpp
index 9a1101a..f5a0887 100644
--- a/services/camera/libcameraservice/CameraService.cpp
+++ b/services/camera/libcameraservice/CameraService.cpp
@@ -33,7 +33,6 @@
 #include <binder/MemoryBase.h>
 #include <binder/MemoryHeapBase.h>
 #include <binder/ProcessInfoService.h>
-#include <camera/ICameraServiceProxy.h>
 #include <cutils/atomic.h>
 #include <cutils/properties.h>
 #include <gui/Surface.h>
@@ -250,13 +249,19 @@
     CameraService::pingCameraServiceProxy();
 }
 
-void CameraService::pingCameraServiceProxy() {
+sp<ICameraServiceProxy> CameraService::getCameraServiceProxy() {
     sp<IServiceManager> sm = defaultServiceManager();
     sp<IBinder> binder = sm->getService(String16("media.camera.proxy"));
     if (binder == nullptr) {
-        return;
+        return nullptr;
     }
     sp<ICameraServiceProxy> proxyBinder = interface_cast<ICameraServiceProxy>(binder);
+    return proxyBinder;
+}
+
+void CameraService::pingCameraServiceProxy() {
+    sp<ICameraServiceProxy> proxyBinder = getCameraServiceProxy();
+    if (proxyBinder == nullptr) return;
     proxyBinder->pingForUserUpdate();
 }
 
@@ -597,6 +602,11 @@
                 procState);
         return -1;
     }
+    // Treat sleeping TOP processes the same as regular TOP processes, for
+    // access priority.  This is important for lock-screen camera launch scenarios
+    if (procState == PROCESS_STATE_TOP_SLEEPING) {
+        procState = PROCESS_STATE_TOP;
+    }
     return INT_MAX - procState;
 }
 
@@ -1948,6 +1958,10 @@
     mCameraService->updateStatus(ICameraServiceListener::STATUS_NOT_AVAILABLE,
             String8::format("%d", mCameraId));
 
+    // Transition device state to OPEN
+    mCameraService->updateProxyDeviceState(ICameraServiceProxy::CAMERA_STATE_OPEN,
+            String8::format("%d", mCameraId));
+
     return OK;
 }
 
@@ -1966,6 +1980,10 @@
         mCameraService->updateStatus(ICameraServiceListener::STATUS_PRESENT,
                 String8::format("%d", mCameraId), rejected);
 
+        // Transition device state to CLOSED
+        mCameraService->updateProxyDeviceState(ICameraServiceProxy::CAMERA_STATE_CLOSED,
+                String8::format("%d", mCameraId));
+
         // Notify flashlight that a camera device is closed.
         mCameraService->mFlashlight->deviceClosed(
                 String8::format("%d", mCameraId));
@@ -2466,6 +2484,14 @@
         });
 }
 
+void CameraService::updateProxyDeviceState(ICameraServiceProxy::CameraState newState,
+        const String8& cameraId) {
+    sp<ICameraServiceProxy> proxyBinder = getCameraServiceProxy();
+    if (proxyBinder == nullptr) return;
+    String16 id(cameraId);
+    proxyBinder->notifyCameraState(id, newState);
+}
+
 status_t CameraService::getTorchStatusLocked(
         const String8& cameraId,
         ICameraServiceListener::TorchStatus *status) const {
diff --git a/services/camera/libcameraservice/CameraService.h b/services/camera/libcameraservice/CameraService.h
index b56c161..330a19d 100644
--- a/services/camera/libcameraservice/CameraService.h
+++ b/services/camera/libcameraservice/CameraService.h
@@ -24,6 +24,7 @@
 #include <binder/BinderService.h>
 #include <binder/IAppOpsCallback.h>
 #include <camera/ICameraService.h>
+#include <camera/ICameraServiceProxy.h>
 #include <hardware/camera.h>
 
 #include <camera/ICamera.h>
@@ -74,6 +75,8 @@
 
     // Process state (mirrors frameworks/base/core/java/android/app/ActivityManager.java)
     static const int PROCESS_STATE_NONEXISTENT = -1;
+    static const int PROCESS_STATE_TOP = 2;
+    static const int PROCESS_STATE_TOP_SLEEPING = 5;
 
     // 3 second busy timeout when other clients are connecting
     static const nsecs_t DEFAULT_CONNECT_TIMEOUT_NS = 3000000000;
@@ -164,6 +167,14 @@
     void                playSound(sound_kind kind);
     void                releaseSound();
 
+    /**
+     * Update the state of a given camera device (open/close/active/idle) with
+     * the camera proxy service in the system service
+     */
+    static void         updateProxyDeviceState(
+            ICameraServiceProxy::CameraState newState,
+            const String8& cameraId);
+
     /////////////////////////////////////////////////////////////////////
     // CameraDeviceFactory functionality
     int                 getDeviceVersion(int cameraId, int* facing = NULL);
@@ -730,6 +741,7 @@
 
     static String8 toString(std::set<userid_t> intSet);
 
+    static sp<ICameraServiceProxy> getCameraServiceProxy();
     static void pingCameraServiceProxy();
 
 };
diff --git a/services/camera/libcameraservice/api1/Camera2Client.cpp b/services/camera/libcameraservice/api1/Camera2Client.cpp
index 36e99dd..48b5a26 100644
--- a/services/camera/libcameraservice/api1/Camera2Client.cpp
+++ b/services/camera/libcameraservice/api1/Camera2Client.cpp
@@ -1912,6 +1912,8 @@
     ALOGV("%s: Shutter notification for request id %" PRId32 " at time %" PRId64,
             __FUNCTION__, resultExtras.requestId, timestamp);
     mCaptureSequencer->notifyShutter(resultExtras, timestamp);
+
+    Camera2ClientBase::notifyShutter(resultExtras, timestamp);
 }
 
 camera2::SharedParameters& Camera2Client::getParameters() {
diff --git a/services/camera/libcameraservice/api1/CameraClient.cpp b/services/camera/libcameraservice/api1/CameraClient.cpp
index e552633..38e35cd 100644
--- a/services/camera/libcameraservice/api1/CameraClient.cpp
+++ b/services/camera/libcameraservice/api1/CameraClient.cpp
@@ -251,6 +251,9 @@
     // Turn off all messages.
     disableMsgType(CAMERA_MSG_ALL_MSGS);
     mHardware->stopPreview();
+    mCameraService->updateProxyDeviceState(
+        ICameraServiceProxy::CAMERA_STATE_IDLE,
+        String8::format("%d", mCameraId));
     mHardware->cancelPicture();
     // Release the hardware resources.
     mHardware->release();
@@ -409,7 +412,11 @@
     }
     mHardware->setPreviewWindow(mPreviewWindow);
     result = mHardware->startPreview();
-
+    if (result == NO_ERROR) {
+        mCameraService->updateProxyDeviceState(
+            ICameraServiceProxy::CAMERA_STATE_ACTIVE,
+            String8::format("%d", mCameraId));
+    }
     return result;
 }
 
@@ -449,7 +456,9 @@
 
     disableMsgType(CAMERA_MSG_PREVIEW_FRAME);
     mHardware->stopPreview();
-
+    mCameraService->updateProxyDeviceState(
+        ICameraServiceProxy::CAMERA_STATE_IDLE,
+        String8::format("%d", mCameraId));
     mPreviewBuffer.clear();
 }
 
@@ -790,6 +799,12 @@
     }
     disableMsgType(CAMERA_MSG_SHUTTER);
 
+    // Shutters only happen in response to takePicture, so mark device as
+    // idle now, until preview is restarted
+    mCameraService->updateProxyDeviceState(
+        ICameraServiceProxy::CAMERA_STATE_IDLE,
+        String8::format("%d", mCameraId));
+
     mLock.unlock();
 }
 
diff --git a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
index c717a56..0c531c3 100644
--- a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
+++ b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
@@ -719,6 +719,43 @@
     return res;
 }
 
+status_t CameraDeviceClient::prepare2(int maxCount, int streamId) {
+    ATRACE_CALL();
+    ALOGV("%s", __FUNCTION__);
+
+    status_t res = OK;
+    if ( (res = checkPid(__FUNCTION__) ) != OK) return res;
+
+    Mutex::Autolock icl(mBinderSerializationLock);
+
+    // Guard against trying to prepare non-created streams
+    ssize_t index = NAME_NOT_FOUND;
+    for (size_t i = 0; i < mStreamMap.size(); ++i) {
+        if (streamId == mStreamMap.valueAt(i)) {
+            index = i;
+            break;
+        }
+    }
+
+    if (index == NAME_NOT_FOUND) {
+        ALOGW("%s: Camera %d: Invalid stream ID (%d) specified, no stream created yet",
+                __FUNCTION__, mCameraId, streamId);
+        return BAD_VALUE;
+    }
+
+    if (maxCount <= 0) {
+        ALOGE("%s: Camera %d: Invalid maxCount (%d) specified, must be greater than 0.",
+                __FUNCTION__, mCameraId, maxCount);
+        return BAD_VALUE;
+    }
+
+    // Also returns BAD_VALUE if stream ID was not valid, or stream already
+    // has been used
+    res = mDevice->prepare(maxCount, streamId);
+
+    return res;
+}
+
 status_t CameraDeviceClient::tearDown(int streamId) {
     ATRACE_CALL();
     ALOGV("%s", __FUNCTION__);
@@ -799,6 +836,7 @@
     if (remoteCb != 0) {
         remoteCb->onDeviceIdle();
     }
+    Camera2ClientBase::notifyIdle();
 }
 
 void CameraDeviceClient::notifyShutter(const CaptureResultExtras& resultExtras,
@@ -808,6 +846,7 @@
     if (remoteCb != 0) {
         remoteCb->onCaptureStarted(resultExtras, timestamp);
     }
+    Camera2ClientBase::notifyShutter(resultExtras, timestamp);
 }
 
 void CameraDeviceClient::notifyPrepared(int streamId) {
diff --git a/services/camera/libcameraservice/api2/CameraDeviceClient.h b/services/camera/libcameraservice/api2/CameraDeviceClient.h
index 1f8b39d..d1e692c 100644
--- a/services/camera/libcameraservice/api2/CameraDeviceClient.h
+++ b/services/camera/libcameraservice/api2/CameraDeviceClient.h
@@ -114,6 +114,9 @@
     // Tear down stream resources by freeing its unused buffers
     virtual status_t      tearDown(int streamId);
 
+    // Prepare stream by preallocating up to maxCount of its buffers
+    virtual status_t      prepare2(int maxCount, int streamId);
+
     /**
      * Interface used by CameraService
      */
@@ -189,6 +192,7 @@
     Vector<int> mStreamingRequestList;
 
     int32_t mRequestIdCounter;
+
 };
 
 }; // namespace android
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.cpp b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
index ba0b264..5732f80 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.cpp
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
@@ -55,7 +55,8 @@
         TClientBase(cameraService, remoteCallback, clientPackageName,
                 cameraId, cameraFacing, clientPid, clientUid, servicePid),
         mSharedCameraCallbacks(remoteCallback),
-        mDeviceVersion(cameraService->getDeviceVersion(cameraId))
+        mDeviceVersion(cameraService->getDeviceVersion(cameraId)),
+        mDeviceActive(false)
 {
     ALOGI("Camera %d: Opened. Client: %s (PID %d, UID %d)", cameraId,
             String8(clientPackageName).string(), clientPid, clientUid);
@@ -235,6 +236,13 @@
 
 template <typename TClientBase>
 void Camera2ClientBase<TClientBase>::notifyIdle() {
+    if (mDeviceActive) {
+        getCameraService()->updateProxyDeviceState(
+            ICameraServiceProxy::CAMERA_STATE_IDLE,
+            String8::format("%d", TClientBase::mCameraId));
+    }
+    mDeviceActive = false;
+
     ALOGV("Camera device is now idle");
 }
 
@@ -244,6 +252,13 @@
     (void)resultExtras;
     (void)timestamp;
 
+    if (!mDeviceActive) {
+        getCameraService()->updateProxyDeviceState(
+            ICameraServiceProxy::CAMERA_STATE_ACTIVE,
+            String8::format("%d", TClientBase::mCameraId));
+    }
+    mDeviceActive = true;
+
     ALOGV("%s: Shutter notification for request id %" PRId32 " at time %" PRId64,
             __FUNCTION__, resultExtras.requestId, timestamp);
 }
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.h b/services/camera/libcameraservice/common/Camera2ClientBase.h
index f1cacdf..220c5ad 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.h
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.h
@@ -136,6 +136,8 @@
     status_t              checkPid(const char *checkLocation) const;
 
     virtual void          detachDevice();
+
+    bool                  mDeviceActive;
 };
 
 }; // namespace android
diff --git a/services/camera/libcameraservice/common/CameraDeviceBase.h b/services/camera/libcameraservice/common/CameraDeviceBase.h
index cd25949..7b083a3 100644
--- a/services/camera/libcameraservice/common/CameraDeviceBase.h
+++ b/services/camera/libcameraservice/common/CameraDeviceBase.h
@@ -294,6 +294,12 @@
     virtual status_t tearDown(int streamId) = 0;
 
     /**
+     * Prepare stream by preallocating up to maxCount buffers for it asynchronously.
+     * Calls notifyPrepared() once allocation is complete.
+     */
+    virtual status_t prepare(int maxCount, int streamId) = 0;
+
+    /**
      * Get the HAL device version.
      */
     virtual uint32_t getDeviceVersion() = 0;
diff --git a/services/camera/libcameraservice/device2/Camera2Device.cpp b/services/camera/libcameraservice/device2/Camera2Device.cpp
index c9c990c..d74f976 100644
--- a/services/camera/libcameraservice/device2/Camera2Device.cpp
+++ b/services/camera/libcameraservice/device2/Camera2Device.cpp
@@ -632,6 +632,12 @@
     return NO_INIT;
 }
 
+status_t Camera2Device::prepare(int maxCount, int streamId) {
+    ATRACE_CALL();
+    ALOGE("%s: Camera %d: unimplemented", __FUNCTION__, mId);
+    return NO_INIT;
+}
+
 uint32_t Camera2Device::getDeviceVersion() {
     ATRACE_CALL();
     return mDeviceVersion;
diff --git a/services/camera/libcameraservice/device2/Camera2Device.h b/services/camera/libcameraservice/device2/Camera2Device.h
index 34c1ded..b4d343c 100644
--- a/services/camera/libcameraservice/device2/Camera2Device.h
+++ b/services/camera/libcameraservice/device2/Camera2Device.h
@@ -88,6 +88,7 @@
     // Prepare and tearDown are no-ops
     virtual status_t prepare(int streamId);
     virtual status_t tearDown(int streamId);
+    virtual status_t prepare(int maxCount, int streamId);
 
     virtual uint32_t getDeviceVersion();
     virtual ssize_t getJpegBufferSize(uint32_t width, uint32_t height) const;
diff --git a/services/camera/libcameraservice/device3/Camera3Device.cpp b/services/camera/libcameraservice/device3/Camera3Device.cpp
index 0c941fb..98d0a41 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.cpp
+++ b/services/camera/libcameraservice/device3/Camera3Device.cpp
@@ -285,19 +285,27 @@
         mStatusTracker->join();
     }
 
+    camera3_device_t *hal3Device;
     {
         Mutex::Autolock l(mLock);
 
         mRequestThread.clear();
         mStatusTracker.clear();
 
-        if (mHal3Device != NULL) {
-            ATRACE_BEGIN("camera3->close");
-            mHal3Device->common.close(&mHal3Device->common);
-            ATRACE_END();
-            mHal3Device = NULL;
-        }
+        hal3Device = mHal3Device;
+    }
 
+    // Call close without internal mutex held, as the HAL close may need to
+    // wait on assorted callbacks,etc, to complete before it can return.
+    if (hal3Device != NULL) {
+        ATRACE_BEGIN("camera3->close");
+        hal3Device->common.close(&hal3Device->common);
+        ATRACE_END();
+    }
+
+    {
+        Mutex::Autolock l(mLock);
+        mHal3Device = NULL;
         internalUpdateStatusLocked(STATUS_UNINITIALIZED);
     }
 
@@ -557,6 +565,18 @@
 
         ALOGV("%s: requestId = %" PRId32, __FUNCTION__, newRequest->mResultExtras.requestId);
     }
+
+    // Setup batch size if this is a high speed video recording request.
+    if (mIsConstrainedHighSpeedConfiguration && requestList->size() > 0) {
+        auto firstRequest = requestList->begin();
+        for (auto& outputStream : (*firstRequest)->mOutputStreams) {
+            if (outputStream->isVideoStream()) {
+                (*firstRequest)->mBatchSize = requestList->size();
+                break;
+            }
+        }
+    }
+
     return OK;
 }
 
@@ -1398,7 +1418,7 @@
 
     status_t res;
     if (mHal3Device->common.version >= CAMERA_DEVICE_API_VERSION_3_1) {
-        res = mHal3Device->ops->flush(mHal3Device);
+        res = mRequestThread->flush();
     } else {
         Mutex::Autolock l(mLock);
         res = waitUntilDrainedLocked();
@@ -1408,6 +1428,10 @@
 }
 
 status_t Camera3Device::prepare(int streamId) {
+    return prepare(camera3::Camera3StreamInterface::ALLOCATE_PIPELINE_MAX, streamId);
+}
+
+status_t Camera3Device::prepare(int maxCount, int streamId) {
     ATRACE_CALL();
     ALOGV("%s: Camera %d: Preparing stream %d", __FUNCTION__, mId, streamId);
     Mutex::Autolock il(mInterfaceLock);
@@ -1432,7 +1456,7 @@
         return BAD_VALUE;
     }
 
-    return mPreparerThread->prepare(stream);
+    return mPreparerThread->prepare(maxCount, stream);
 }
 
 status_t Camera3Device::tearDown(int streamId) {
@@ -1583,6 +1607,7 @@
         newRequest->mOutputStreams.push(stream);
     }
     newRequest->mSettings.erase(ANDROID_REQUEST_OUTPUT_STREAMS);
+    newRequest->mBatchSize = 1;
 
     return newRequest;
 }
@@ -2754,6 +2779,17 @@
     return OK;
 }
 
+status_t Camera3Device::RequestThread::flush() {
+    ATRACE_CALL();
+    Mutex::Autolock l(mFlushLock);
+
+    if (mHal3Device->common.version >= CAMERA_DEVICE_API_VERSION_3_1) {
+        return mHal3Device->ops->flush(mHal3Device);
+    }
+
+    return -ENOTSUP;
+}
+
 void Camera3Device::RequestThread::setPaused(bool paused) {
     Mutex::Autolock l(mPauseLock);
     mDoPause = paused;
@@ -2844,7 +2880,7 @@
 }
 
 bool Camera3Device::RequestThread::threadLoop() {
-
+    ATRACE_CALL();
     status_t res;
 
     // Handle paused state.
@@ -2852,147 +2888,33 @@
         return true;
     }
 
-    // Get work to do
-
-    sp<CaptureRequest> nextRequest = waitForNextRequest();
-    if (nextRequest == NULL) {
+    // Get next batch of requests.
+    Vector<NextRequest> nextRequests;
+    waitForNextRequestBatch(&nextRequests);
+    const size_t numRequests = nextRequests.size();
+    if (numRequests == 0) {
         return true;
     }
 
-    // Create request to HAL
-    camera3_capture_request_t request = camera3_capture_request_t();
-    request.frame_number = nextRequest->mResultExtras.frameNumber;
-    Vector<camera3_stream_buffer_t> outputBuffers;
-
-    // Get the request ID, if any
-    int requestId;
-    camera_metadata_entry_t requestIdEntry =
-            nextRequest->mSettings.find(ANDROID_REQUEST_ID);
+    // Get the latest request ID, if any
+    int latestRequestId;
+    camera_metadata_entry_t requestIdEntry = nextRequests[nextRequests.size() - 1].
+            captureRequest->mSettings.find(ANDROID_REQUEST_ID);
     if (requestIdEntry.count > 0) {
-        requestId = requestIdEntry.data.i32[0];
+        latestRequestId = requestIdEntry.data.i32[0];
     } else {
-        ALOGW("%s: Did not have android.request.id set in the request",
-                __FUNCTION__);
-        requestId = NAME_NOT_FOUND;
+        ALOGW("%s: Did not have android.request.id set in the request.", __FUNCTION__);
+        latestRequestId = NAME_NOT_FOUND;
     }
 
-    // Insert any queued triggers (before metadata is locked)
-    int32_t triggerCount;
-    res = insertTriggers(nextRequest);
-    if (res < 0) {
-        SET_ERR("RequestThread: Unable to insert triggers "
-                "(capture request %d, HAL device: %s (%d)",
-                request.frame_number, strerror(-res), res);
-        cleanUpFailedRequest(request, nextRequest, outputBuffers);
-        return false;
-    }
-    triggerCount = res;
-
-    bool triggersMixedIn = (triggerCount > 0 || mPrevTriggers > 0);
-
-    // If the request is the same as last, or we had triggers last time
-    if (mPrevRequest != nextRequest || triggersMixedIn) {
-        /**
-         * HAL workaround:
-         * Insert a dummy trigger ID if a trigger is set but no trigger ID is
-         */
-        res = addDummyTriggerIds(nextRequest);
-        if (res != OK) {
-            SET_ERR("RequestThread: Unable to insert dummy trigger IDs "
-                    "(capture request %d, HAL device: %s (%d)",
-                    request.frame_number, strerror(-res), res);
-            cleanUpFailedRequest(request, nextRequest, outputBuffers);
-            return false;
-        }
-
-        /**
-         * The request should be presorted so accesses in HAL
-         *   are O(logn). Sidenote, sorting a sorted metadata is nop.
-         */
-        nextRequest->mSettings.sort();
-        request.settings = nextRequest->mSettings.getAndLock();
-        mPrevRequest = nextRequest;
-        ALOGVV("%s: Request settings are NEW", __FUNCTION__);
-
-        IF_ALOGV() {
-            camera_metadata_ro_entry_t e = camera_metadata_ro_entry_t();
-            find_camera_metadata_ro_entry(
-                    request.settings,
-                    ANDROID_CONTROL_AF_TRIGGER,
-                    &e
-            );
-            if (e.count > 0) {
-                ALOGV("%s: Request (frame num %d) had AF trigger 0x%x",
-                      __FUNCTION__,
-                      request.frame_number,
-                      e.data.u8[0]);
-            }
-        }
-    } else {
-        // leave request.settings NULL to indicate 'reuse latest given'
-        ALOGVV("%s: Request settings are REUSED",
-               __FUNCTION__);
-    }
-
-    uint32_t totalNumBuffers = 0;
-
-    // Fill in buffers
-    if (nextRequest->mInputStream != NULL) {
-        request.input_buffer = &nextRequest->mInputBuffer;
-        totalNumBuffers += 1;
-    } else {
-        request.input_buffer = NULL;
-    }
-
-    outputBuffers.insertAt(camera3_stream_buffer_t(), 0,
-            nextRequest->mOutputStreams.size());
-    request.output_buffers = outputBuffers.array();
-    for (size_t i = 0; i < nextRequest->mOutputStreams.size(); i++) {
-        res = nextRequest->mOutputStreams.editItemAt(i)->
-                getBuffer(&outputBuffers.editItemAt(i));
-        if (res != OK) {
-            // Can't get output buffer from gralloc queue - this could be due to
-            // abandoned queue or other consumer misbehavior, so not a fatal
-            // error
-            ALOGE("RequestThread: Can't get output buffer, skipping request:"
-                    " %s (%d)", strerror(-res), res);
-            {
-                Mutex::Autolock l(mRequestLock);
-                if (mListener != NULL) {
-                    mListener->notifyError(
-                            ICameraDeviceCallbacks::ERROR_CAMERA_REQUEST,
-                            nextRequest->mResultExtras);
-                }
-            }
-            cleanUpFailedRequest(request, nextRequest, outputBuffers);
-            return true;
-        }
-        request.num_output_buffers++;
-    }
-    totalNumBuffers += request.num_output_buffers;
-
-    // Log request in the in-flight queue
-    sp<Camera3Device> parent = mParent.promote();
-    if (parent == NULL) {
-        // Should not happen, and nowhere to send errors to, so just log it
-        CLOGE("RequestThread: Parent is gone");
-        cleanUpFailedRequest(request, nextRequest, outputBuffers);
-        return false;
-    }
-
-    res = parent->registerInFlight(request.frame_number,
-            totalNumBuffers, nextRequest->mResultExtras,
-            /*hasInput*/request.input_buffer != NULL,
-            nextRequest->mAeTriggerCancelOverride);
-    ALOGVV("%s: registered in flight requestId = %" PRId32 ", frameNumber = %" PRId64
-           ", burstId = %" PRId32 ".",
-            __FUNCTION__,
-            nextRequest->mResultExtras.requestId, nextRequest->mResultExtras.frameNumber,
-            nextRequest->mResultExtras.burstId);
-    if (res != OK) {
-        SET_ERR("RequestThread: Unable to register new in-flight request:"
-                " %s (%d)", strerror(-res), res);
-        cleanUpFailedRequest(request, nextRequest, outputBuffers);
+    // Prepare a batch of HAL requests and output buffers.
+    res = prepareHalRequests(&nextRequests);
+    if (res == TIMED_OUT) {
+        // Not a fatal error if getting output buffers time out.
+        cleanUpFailedRequests(&nextRequests, /*sendRequestError*/ true);
+        return true;
+    } else if (res != OK) {
+        cleanUpFailedRequests(&nextRequests, /*sendRequestError*/ false);
         return false;
     }
 
@@ -3000,57 +2922,214 @@
     {
         Mutex::Autolock al(mLatestRequestMutex);
 
-        mLatestRequestId = requestId;
+        mLatestRequestId = latestRequestId;
         mLatestRequestSignal.signal();
     }
 
-    // Submit request and block until ready for next one
-    ATRACE_ASYNC_BEGIN("frame capture", request.frame_number);
-    ATRACE_BEGIN("camera3->process_capture_request");
-    res = mHal3Device->ops->process_capture_request(mHal3Device, &request);
-    ATRACE_END();
+    // Submit a batch of requests to HAL.
+    // Use flush lock only when submitting multilple requests in a batch.
+    // TODO: The problem with flush lock is flush() will be blocked by process_capture_request()
+    // which may take a long time to finish so synchronizing flush() and
+    // process_capture_request() defeats the purpose of cancelling requests ASAP with flush().
+    // For now, only synchronize for high speed recording and we should figure something out for
+    // removing the synchronization.
+    bool useFlushLock = nextRequests.size() > 1;
 
-    if (res != OK) {
-        // Should only get a failure here for malformed requests or device-level
-        // errors, so consider all errors fatal.  Bad metadata failures should
-        // come through notify.
-        SET_ERR("RequestThread: Unable to submit capture request %d to HAL"
-                " device: %s (%d)", request.frame_number, strerror(-res), res);
-        cleanUpFailedRequest(request, nextRequest, outputBuffers);
-        return false;
+    if (useFlushLock) {
+        mFlushLock.lock();
     }
 
-    // Update the latest request sent to HAL
-    if (request.settings != NULL) { // Don't update them if they were unchanged
-        Mutex::Autolock al(mLatestRequestMutex);
+    ALOGVV("%s: %d: submitting %d requests in a batch.", __FUNCTION__, __LINE__,
+            nextRequests.size());
+    for (auto& nextRequest : nextRequests) {
+        // Submit request and block until ready for next one
+        ATRACE_ASYNC_BEGIN("frame capture", nextRequest.halRequest.frame_number);
+        ATRACE_BEGIN("camera3->process_capture_request");
+        res = mHal3Device->ops->process_capture_request(mHal3Device, &nextRequest.halRequest);
+        ATRACE_END();
 
-        camera_metadata_t* cloned = clone_camera_metadata(request.settings);
-        mLatestRequest.acquire(cloned);
+        if (res != OK) {
+            // Should only get a failure here for malformed requests or device-level
+            // errors, so consider all errors fatal.  Bad metadata failures should
+            // come through notify.
+            SET_ERR("RequestThread: Unable to submit capture request %d to HAL"
+                    " device: %s (%d)", nextRequest.halRequest.frame_number, strerror(-res),
+                    res);
+            cleanUpFailedRequests(&nextRequests, /*sendRequestError*/ false);
+            if (useFlushLock) {
+                mFlushLock.unlock();
+            }
+            return false;
+        }
+
+        // Mark that the request has be submitted successfully.
+        nextRequest.submitted = true;
+
+        // Update the latest request sent to HAL
+        if (nextRequest.halRequest.settings != NULL) { // Don't update if they were unchanged
+            Mutex::Autolock al(mLatestRequestMutex);
+
+            camera_metadata_t* cloned = clone_camera_metadata(nextRequest.halRequest.settings);
+            mLatestRequest.acquire(cloned);
+        }
+
+        if (nextRequest.halRequest.settings != NULL) {
+            nextRequest.captureRequest->mSettings.unlock(nextRequest.halRequest.settings);
+        }
+
+        // Remove any previously queued triggers (after unlock)
+        res = removeTriggers(mPrevRequest);
+        if (res != OK) {
+            SET_ERR("RequestThread: Unable to remove triggers "
+                  "(capture request %d, HAL device: %s (%d)",
+                  nextRequest.halRequest.frame_number, strerror(-res), res);
+            cleanUpFailedRequests(&nextRequests, /*sendRequestError*/ false);
+            if (useFlushLock) {
+                mFlushLock.unlock();
+            }
+            return false;
+        }
     }
 
-    if (request.settings != NULL) {
-        nextRequest->mSettings.unlock(request.settings);
+    if (useFlushLock) {
+        mFlushLock.unlock();
     }
 
     // Unset as current request
     {
         Mutex::Autolock l(mRequestLock);
-        mNextRequest.clear();
+        mNextRequests.clear();
     }
 
-    // Remove any previously queued triggers (after unlock)
-    res = removeTriggers(mPrevRequest);
-    if (res != OK) {
-        SET_ERR("RequestThread: Unable to remove triggers "
-              "(capture request %d, HAL device: %s (%d)",
-              request.frame_number, strerror(-res), res);
-        return false;
-    }
-    mPrevTriggers = triggerCount;
-
     return true;
 }
 
+status_t Camera3Device::RequestThread::prepareHalRequests(Vector<NextRequest> *nextRequests) {
+    ATRACE_CALL();
+
+    if (nextRequests == nullptr) {
+        return BAD_VALUE;
+    }
+
+    for (auto& nextRequest : *nextRequests) {
+        sp<CaptureRequest> captureRequest = nextRequest.captureRequest;
+        camera3_capture_request_t* halRequest = &nextRequest.halRequest;
+        Vector<camera3_stream_buffer_t>* outputBuffers = &nextRequest.outputBuffers;
+
+        // Prepare a request to HAL
+        halRequest->frame_number = captureRequest->mResultExtras.frameNumber;
+
+        // Insert any queued triggers (before metadata is locked)
+        status_t res = insertTriggers(captureRequest);
+
+        if (res < 0) {
+            SET_ERR("RequestThread: Unable to insert triggers "
+                    "(capture request %d, HAL device: %s (%d)",
+                    halRequest->frame_number, strerror(-res), res);
+            return INVALID_OPERATION;
+        }
+        int triggerCount = res;
+        bool triggersMixedIn = (triggerCount > 0 || mPrevTriggers > 0);
+        mPrevTriggers = triggerCount;
+
+        // If the request is the same as last, or we had triggers last time
+        if (mPrevRequest != captureRequest || triggersMixedIn) {
+            /**
+             * HAL workaround:
+             * Insert a dummy trigger ID if a trigger is set but no trigger ID is
+             */
+            res = addDummyTriggerIds(captureRequest);
+            if (res != OK) {
+                SET_ERR("RequestThread: Unable to insert dummy trigger IDs "
+                        "(capture request %d, HAL device: %s (%d)",
+                        halRequest->frame_number, strerror(-res), res);
+                return INVALID_OPERATION;
+            }
+
+            /**
+             * The request should be presorted so accesses in HAL
+             *   are O(logn). Sidenote, sorting a sorted metadata is nop.
+             */
+            captureRequest->mSettings.sort();
+            halRequest->settings = captureRequest->mSettings.getAndLock();
+            mPrevRequest = captureRequest;
+            ALOGVV("%s: Request settings are NEW", __FUNCTION__);
+
+            IF_ALOGV() {
+                camera_metadata_ro_entry_t e = camera_metadata_ro_entry_t();
+                find_camera_metadata_ro_entry(
+                        halRequest->settings,
+                        ANDROID_CONTROL_AF_TRIGGER,
+                        &e
+                );
+                if (e.count > 0) {
+                    ALOGV("%s: Request (frame num %d) had AF trigger 0x%x",
+                          __FUNCTION__,
+                          halRequest->frame_number,
+                          e.data.u8[0]);
+                }
+            }
+        } else {
+            // leave request.settings NULL to indicate 'reuse latest given'
+            ALOGVV("%s: Request settings are REUSED",
+                   __FUNCTION__);
+        }
+
+        uint32_t totalNumBuffers = 0;
+
+        // Fill in buffers
+        if (captureRequest->mInputStream != NULL) {
+            halRequest->input_buffer = &captureRequest->mInputBuffer;
+            totalNumBuffers += 1;
+        } else {
+            halRequest->input_buffer = NULL;
+        }
+
+        outputBuffers->insertAt(camera3_stream_buffer_t(), 0,
+                captureRequest->mOutputStreams.size());
+        halRequest->output_buffers = outputBuffers->array();
+        for (size_t i = 0; i < captureRequest->mOutputStreams.size(); i++) {
+            res = captureRequest->mOutputStreams.editItemAt(i)->
+                    getBuffer(&outputBuffers->editItemAt(i));
+            if (res != OK) {
+                // Can't get output buffer from gralloc queue - this could be due to
+                // abandoned queue or other consumer misbehavior, so not a fatal
+                // error
+                ALOGE("RequestThread: Can't get output buffer, skipping request:"
+                        " %s (%d)", strerror(-res), res);
+
+                return TIMED_OUT;
+            }
+            halRequest->num_output_buffers++;
+        }
+        totalNumBuffers += halRequest->num_output_buffers;
+
+        // Log request in the in-flight queue
+        sp<Camera3Device> parent = mParent.promote();
+        if (parent == NULL) {
+            // Should not happen, and nowhere to send errors to, so just log it
+            CLOGE("RequestThread: Parent is gone");
+            return INVALID_OPERATION;
+        }
+        res = parent->registerInFlight(halRequest->frame_number,
+                totalNumBuffers, captureRequest->mResultExtras,
+                /*hasInput*/halRequest->input_buffer != NULL,
+                captureRequest->mAeTriggerCancelOverride);
+        ALOGVV("%s: registered in flight requestId = %" PRId32 ", frameNumber = %" PRId64
+               ", burstId = %" PRId32 ".",
+                __FUNCTION__,
+                captureRequest->mResultExtras.requestId, captureRequest->mResultExtras.frameNumber,
+                captureRequest->mResultExtras.burstId);
+        if (res != OK) {
+            SET_ERR("RequestThread: Unable to register new in-flight request:"
+                    " %s (%d)", strerror(-res), res);
+            return INVALID_OPERATION;
+        }
+    }
+
+    return OK;
+}
+
 CameraMetadata Camera3Device::RequestThread::getLatestRequest() const {
     Mutex::Autolock al(mLatestRequestMutex);
 
@@ -3063,11 +3142,11 @@
         sp<Camera3StreamInterface>& stream) {
     Mutex::Autolock l(mRequestLock);
 
-    if (mNextRequest != nullptr) {
-        for (const auto& s : mNextRequest->mOutputStreams) {
+    for (const auto& nextRequest : mNextRequests) {
+        for (const auto& s : nextRequest->mOutputStreams) {
             if (stream == s) return true;
         }
-        if (stream == mNextRequest->mInputStream) return true;
+        if (stream == nextRequest->mInputStream) return true;
     }
 
     for (const auto& request : mRequestQueue) {
@@ -3087,37 +3166,104 @@
     return false;
 }
 
-void Camera3Device::RequestThread::cleanUpFailedRequest(
-        camera3_capture_request_t &request,
-        sp<CaptureRequest> &nextRequest,
-        Vector<camera3_stream_buffer_t> &outputBuffers) {
+void Camera3Device::RequestThread::cleanUpFailedRequests(Vector<NextRequest> *nextRequests,
+        bool sendRequestError) {
+    if (nextRequests == nullptr) {
+        return;
+    }
 
-    if (request.settings != NULL) {
-        nextRequest->mSettings.unlock(request.settings);
-    }
-    if (nextRequest->mInputStream != NULL) {
-        nextRequest->mInputBuffer.status = CAMERA3_BUFFER_STATUS_ERROR;
-        nextRequest->mInputStream->returnInputBuffer(nextRequest->mInputBuffer);
-    }
-    for (size_t i = 0; i < request.num_output_buffers; i++) {
-        outputBuffers.editItemAt(i).status = CAMERA3_BUFFER_STATUS_ERROR;
-        nextRequest->mOutputStreams.editItemAt(i)->returnBuffer(
-            outputBuffers[i], 0);
+    for (auto& nextRequest : *nextRequests) {
+        // Skip the ones that have been submitted successfully.
+        if (nextRequest.submitted) {
+            continue;
+        }
+
+        sp<CaptureRequest> captureRequest = nextRequest.captureRequest;
+        camera3_capture_request_t* halRequest = &nextRequest.halRequest;
+        Vector<camera3_stream_buffer_t>* outputBuffers = &nextRequest.outputBuffers;
+
+        if (halRequest->settings != NULL) {
+            captureRequest->mSettings.unlock(halRequest->settings);
+        }
+
+        if (captureRequest->mInputStream != NULL) {
+            captureRequest->mInputBuffer.status = CAMERA3_BUFFER_STATUS_ERROR;
+            captureRequest->mInputStream->returnInputBuffer(captureRequest->mInputBuffer);
+        }
+
+        for (size_t i = 0; i < halRequest->num_output_buffers; i++) {
+            outputBuffers->editItemAt(i).status = CAMERA3_BUFFER_STATUS_ERROR;
+            captureRequest->mOutputStreams.editItemAt(i)->returnBuffer((*outputBuffers)[i], 0);
+        }
+
+        if (sendRequestError) {
+            Mutex::Autolock l(mRequestLock);
+            if (mListener != NULL) {
+                mListener->notifyError(
+                        ICameraDeviceCallbacks::ERROR_CAMERA_REQUEST,
+                        captureRequest->mResultExtras);
+            }
+        }
     }
 
     Mutex::Autolock l(mRequestLock);
-    mNextRequest.clear();
+    mNextRequests.clear();
+    nextRequests->clear();
 }
 
-sp<Camera3Device::CaptureRequest>
-        Camera3Device::RequestThread::waitForNextRequest() {
-    status_t res;
-    sp<CaptureRequest> nextRequest;
+void Camera3Device::RequestThread::waitForNextRequestBatch(Vector<NextRequest> *nextRequests) {
+    if (nextRequests == nullptr) {
+        return;
+    }
 
     // Optimized a bit for the simple steady-state case (single repeating
     // request), to avoid putting that request in the queue temporarily.
     Mutex::Autolock l(mRequestLock);
 
+    nextRequests->clear();
+    assert(mNextRequests.empty());
+
+    NextRequest nextRequest;
+    nextRequest.captureRequest = waitForNextRequestLocked();
+    if (nextRequest.captureRequest == nullptr) {
+        return;
+    }
+
+    nextRequest.halRequest = camera3_capture_request_t();
+    nextRequest.submitted = false;
+    nextRequests->add(nextRequest);
+    mNextRequests.push_back(nextRequest.captureRequest);
+
+    // Wait for additional requests
+    const size_t batchSize = nextRequest.captureRequest->mBatchSize;
+
+    for (size_t i = 1; i < batchSize; i++) {
+        NextRequest additionalRequest;
+        additionalRequest.captureRequest = waitForNextRequestLocked();
+        if (additionalRequest.captureRequest == nullptr) {
+            break;
+        }
+
+        additionalRequest.halRequest = camera3_capture_request_t();
+        additionalRequest.submitted = false;
+        nextRequests->add(additionalRequest);
+        mNextRequests.push_back(additionalRequest.captureRequest);
+    }
+
+    if (nextRequests->size() < batchSize) {
+        ALOGE("RequestThread: only get %d out of %d requests. Skipping requests.",
+                nextRequests->size(), batchSize);
+        cleanUpFailedRequests(nextRequests, /*sendRequestError*/true);
+    }
+
+    return;
+}
+
+sp<Camera3Device::CaptureRequest>
+        Camera3Device::RequestThread::waitForNextRequestLocked() {
+    status_t res;
+    sp<CaptureRequest> nextRequest;
+
     while (mRequestQueue.empty()) {
         if (!mRepeatingRequests.empty()) {
             // Always atomically enqueue all requests in a repeating request
@@ -3212,8 +3358,6 @@
 
     handleAePrecaptureCancelRequest(nextRequest);
 
-    mNextRequest = nextRequest;
-
     return nextRequest;
 }
 
@@ -3478,12 +3622,12 @@
     clear();
 }
 
-status_t Camera3Device::PreparerThread::prepare(sp<Camera3StreamInterface>& stream) {
+status_t Camera3Device::PreparerThread::prepare(int maxCount, sp<Camera3StreamInterface>& stream) {
     status_t res;
 
     Mutex::Autolock l(mLock);
 
-    res = stream->startPrepare();
+    res = stream->startPrepare(maxCount);
     if (res == OK) {
         // No preparation needed, fire listener right off
         ALOGV("%s: Stream %d already prepared", __FUNCTION__, stream->getId());
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index 5287058..a3abbaf 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -62,6 +62,7 @@
             public CameraDeviceBase,
             private camera3_callback_ops {
   public:
+
     Camera3Device(int id);
 
     virtual ~Camera3Device();
@@ -143,6 +144,8 @@
 
     virtual status_t tearDown(int streamId);
 
+    virtual status_t prepare(int maxCount, int streamId);
+
     virtual uint32_t getDeviceVersion();
 
     virtual ssize_t getJpegBufferSize(uint32_t width, uint32_t height) const;
@@ -261,6 +264,11 @@
         // Used to cancel AE precapture trigger for devices doesn't support
         // CONTROL_AE_PRECAPTURE_TRIGGER_CANCEL
         AeTriggerCancelOverride_t           mAeTriggerCancelOverride;
+        // The number of requests that should be submitted to HAL at a time.
+        // For example, if batch size is 8, this request and the following 7
+        // requests will be submitted to HAL at a time. The batch size for
+        // the following 7 requests will be ignored by the request thread.
+        int                                 mBatchSize;
     };
     typedef List<sp<CaptureRequest> > RequestList;
 
@@ -438,6 +446,11 @@
                        int64_t *lastFrameNumber = NULL);
 
         /**
+         * Flush all pending requests in HAL.
+         */
+        status_t flush();
+
+        /**
          * Queue a trigger to be dispatched with the next outgoing
          * process_capture_request. The settings for that request only
          * will be temporarily rewritten to add the trigger tag/value.
@@ -498,16 +511,28 @@
 
         static const nsecs_t kRequestTimeout = 50e6; // 50 ms
 
-        // Waits for a request, or returns NULL if times out.
-        sp<CaptureRequest> waitForNextRequest();
+        // Used to prepare a batch of requests.
+        struct NextRequest {
+            sp<CaptureRequest>              captureRequest;
+            camera3_capture_request_t       halRequest;
+            Vector<camera3_stream_buffer_t> outputBuffers;
+            bool                            submitted;
+        };
 
-        // Return buffers, etc, for a request that couldn't be fully
-        // constructed. The buffers will be returned in the ERROR state
-        // to mark them as not having valid data.
-        // All arguments will be modified.
-        void cleanUpFailedRequest(camera3_capture_request_t &request,
-                sp<CaptureRequest> &nextRequest,
-                Vector<camera3_stream_buffer_t> &outputBuffers);
+        // Wait for the next batch of requests.
+        void waitForNextRequestBatch(Vector<NextRequest> *nextRequests);
+
+        // Waits for a request, or returns NULL if times out. Must be called with mRequestLock hold.
+        sp<CaptureRequest> waitForNextRequestLocked();
+
+        // Prepare a HAL request and output buffers. Return TIMED_OUT if getting any output buffer
+        // timed out. If an error is returned, the caller should clean up the pending request batch.
+        status_t prepareHalRequests(Vector<NextRequest> *nextRequests);
+
+        // Return buffers, etc, for a request that couldn't be fully constructed and send request
+        // errors if sendRequestError is true. The buffers will be returned in the ERROR state
+        // to mark them as not having valid data. nextRequests will be modified.
+        void cleanUpFailedRequests(Vector<NextRequest> *nextRequests, bool sendRequestError);
 
         // Pause handling
         bool               waitIfPaused();
@@ -536,10 +561,13 @@
         Condition          mRequestSignal;
         RequestList        mRequestQueue;
         RequestList        mRepeatingRequests;
-        // The next request being prepped for submission to the HAL, no longer
+        // The next requests being prepped for submission to the HAL, no longer
         // on the request queue. Read-only even with mRequestLock held, outside
         // of threadLoop
-        sp<const CaptureRequest> mNextRequest;
+        RequestList        mNextRequests;
+
+        // To protect flush() and sending a request batch to HAL.
+        Mutex              mFlushLock;
 
         bool               mReconfigured;
 
@@ -698,10 +726,11 @@
         void setNotificationListener(NotificationListener *listener);
 
         /**
-         * Queue up a stream to be prepared. Streams are processed by
-         * a background thread in FIFO order
+         * Queue up a stream to be prepared. Streams are processed by a background thread in FIFO
+         * order.  Pre-allocate up to maxCount buffers for the stream, or the maximum number needed
+         * for the pipeline if maxCount is ALLOCATE_PIPELINE_MAX.
          */
-        status_t prepare(sp<camera3::Camera3StreamInterface>& stream);
+        status_t prepare(int maxCount, sp<camera3::Camera3StreamInterface>& stream);
 
         /**
          * Cancel all current and pending stream preparation
diff --git a/services/camera/libcameraservice/device3/Camera3DummyStream.cpp b/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
index ecb8ac8..1d9d04f 100644
--- a/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
+++ b/services/camera/libcameraservice/device3/Camera3DummyStream.cpp
@@ -92,6 +92,10 @@
     return OK;
 }
 
+bool Camera3DummyStream::isVideoStream() const {
+    return false;
+}
+
 }; // namespace camera3
 
 }; // namespace android
diff --git a/services/camera/libcameraservice/device3/Camera3DummyStream.h b/services/camera/libcameraservice/device3/Camera3DummyStream.h
index 3a3dbf4..97c0c96 100644
--- a/services/camera/libcameraservice/device3/Camera3DummyStream.h
+++ b/services/camera/libcameraservice/device3/Camera3DummyStream.h
@@ -54,6 +54,11 @@
 
     status_t         setTransform(int transform);
 
+    /**
+     * Return if this output stream is for video encoding.
+     */
+    bool isVideoStream() const;
+
   protected:
 
     /**
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
index 8c611d5..3f0a736 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp
@@ -426,6 +426,17 @@
     return res;
 }
 
+bool Camera3OutputStream::isVideoStream() const {
+    uint32_t usage = 0;
+    status_t res = getEndpointUsage(&usage);
+    if (res != OK) {
+        ALOGE("%s: getting end point usage failed: %s (%d).", __FUNCTION__, strerror(-res), res);
+        return false;
+    }
+
+    return (usage & GRALLOC_USAGE_HW_VIDEO_ENCODER) != 0;
+}
+
 }; // namespace camera3
 
 }; // namespace android
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.h b/services/camera/libcameraservice/device3/Camera3OutputStream.h
index 941d693..3c083ec 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStream.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStream.h
@@ -64,6 +64,11 @@
      */
     status_t         setTransform(int transform);
 
+    /**
+     * Return if this output stream is for video encoding.
+     */
+    bool isVideoStream() const;
+
   protected:
     Camera3OutputStream(int id, camera3_stream_type_t type,
             uint32_t width, uint32_t height, int format,
diff --git a/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h b/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
index aae72cf..df89b34 100644
--- a/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
+++ b/services/camera/libcameraservice/device3/Camera3OutputStreamInterface.h
@@ -34,6 +34,11 @@
      * HAL_TRANSFORM_* / NATIVE_WINDOW_TRANSFORM_* constants.
      */
     virtual status_t setTransform(int transform) = 0;
+
+    /**
+     * Return if this output stream is for video encoding.
+     */
+    virtual bool isVideoStream() const = 0;
 };
 
 } // namespace camera3
diff --git a/services/camera/libcameraservice/device3/Camera3Stream.cpp b/services/camera/libcameraservice/device3/Camera3Stream.cpp
index 2527fd6..691764f 100644
--- a/services/camera/libcameraservice/device3/Camera3Stream.cpp
+++ b/services/camera/libcameraservice/device3/Camera3Stream.cpp
@@ -53,7 +53,8 @@
     mName(String8::format("Camera3Stream[%d]", id)),
     mMaxSize(maxSize),
     mState(STATE_CONSTRUCTED),
-    mStatusId(StatusTracker::NO_STATUS_ID) {
+    mStatusId(StatusTracker::NO_STATUS_ID),
+    mLastMaxCount(Camera3StreamInterface::ALLOCATE_PIPELINE_MAX) {
 
     camera3_stream::stream_type = type;
     camera3_stream::width = width;
@@ -252,12 +253,18 @@
     return mStreamUnpreparable;
 }
 
-status_t Camera3Stream::startPrepare() {
+status_t Camera3Stream::startPrepare(int maxCount) {
     ATRACE_CALL();
 
     Mutex::Autolock l(mLock);
     status_t res = OK;
 
+    if (maxCount < 0) {
+        ALOGE("%s: Stream %d: Can't prepare stream if max buffer count (%d) is < 0",
+                __FUNCTION__, mId, maxCount);
+        return BAD_VALUE;
+    }
+
     // This function should be only called when the stream is configured already.
     if (mState != STATE_CONFIGURED) {
         ALOGE("%s: Stream %d: Can't prepare stream if stream is not in CONFIGURED "
@@ -279,9 +286,19 @@
         return INVALID_OPERATION;
     }
 
+
+
+    size_t pipelineMax = getBufferCountLocked();
+    size_t clampedCount = (pipelineMax < static_cast<size_t>(maxCount)) ?
+            pipelineMax : static_cast<size_t>(maxCount);
+    size_t bufferCount = (maxCount == Camera3StreamInterface::ALLOCATE_PIPELINE_MAX) ?
+            pipelineMax : clampedCount;
+
+    mPrepared = bufferCount <= mLastMaxCount;
+
     if (mPrepared) return OK;
 
-    size_t bufferCount = getBufferCountLocked();
+    mLastMaxCount = bufferCount;
 
     mPreparedBuffers.insertAt(camera3_stream_buffer_t(), /*index*/0, bufferCount);
     mPreparedBufferIdx = 0;
@@ -438,8 +455,9 @@
         res = mOutputBufferReturnedSignal.waitRelative(mLock, kWaitForBufferDuration);
         if (res != OK) {
             if (res == TIMED_OUT) {
-                ALOGE("%s: wait for output buffer return timed out after %lldms", __FUNCTION__,
-                        kWaitForBufferDuration / 1000000LL);
+                ALOGE("%s: wait for output buffer return timed out after %lldms (max_buffers %d)",
+                        __FUNCTION__, kWaitForBufferDuration / 1000000LL,
+                        camera3_stream::max_buffers);
             }
             return res;
         }
diff --git a/services/camera/libcameraservice/device3/Camera3Stream.h b/services/camera/libcameraservice/device3/Camera3Stream.h
index bab2177..753280b 100644
--- a/services/camera/libcameraservice/device3/Camera3Stream.h
+++ b/services/camera/libcameraservice/device3/Camera3Stream.h
@@ -188,7 +188,9 @@
 
     /**
      * Start stream preparation. May only be called in the CONFIGURED state,
-     * when no valid buffers have yet been returned to this stream.
+     * when no valid buffers have yet been returned to this stream. Prepares
+     * up to maxCount buffers, or the maximum number of buffers needed by the
+     * pipeline if maxCount is ALLOCATE_PIPELINE_MAX.
      *
      * If no prepartion is necessary, returns OK and does not transition to
      * PREPARING state. Otherwise, returns NOT_ENOUGH_DATA and transitions
@@ -204,7 +206,7 @@
      *    INVALID_OPERATION if called when not in CONFIGURED state, or a
      *        valid buffer has already been returned to this stream.
      */
-    status_t         startPrepare();
+    status_t         startPrepare(int maxCount);
 
     /**
      * Check if the stream is mid-preparing.
@@ -444,6 +446,9 @@
     Vector<camera3_stream_buffer_t> mPreparedBuffers;
     size_t mPreparedBufferIdx;
 
+    // Number of buffers allocated on last prepare call.
+    int mLastMaxCount;
+
 }; // class Camera3Stream
 
 }; // namespace camera3
diff --git a/services/camera/libcameraservice/device3/Camera3StreamInterface.h b/services/camera/libcameraservice/device3/Camera3StreamInterface.h
index c086eaf..54009ae 100644
--- a/services/camera/libcameraservice/device3/Camera3StreamInterface.h
+++ b/services/camera/libcameraservice/device3/Camera3StreamInterface.h
@@ -34,6 +34,11 @@
  */
 class Camera3StreamInterface : public virtual RefBase {
   public:
+
+    enum {
+        ALLOCATE_PIPELINE_MAX = 0, // Allocate max buffers used by a given surface
+    };
+
     /**
      * Get the stream's ID
      */
@@ -98,7 +103,9 @@
 
     /**
      * Start stream preparation. May only be called in the CONFIGURED state,
-     * when no valid buffers have yet been returned to this stream.
+     * when no valid buffers have yet been returned to this stream. Prepares
+     * up to maxCount buffers, or the maximum number of buffers needed by the
+     * pipeline if maxCount is ALLOCATE_PIPELINE_MAX.
      *
      * If no prepartion is necessary, returns OK and does not transition to
      * PREPARING state. Otherwise, returns NOT_ENOUGH_DATA and transitions
@@ -112,7 +119,7 @@
      *    INVALID_OPERATION if called when not in CONFIGURED state, or a
      *        valid buffer has already been returned to this stream.
      */
-    virtual status_t startPrepare() = 0;
+    virtual status_t startPrepare(int maxCount) = 0;
 
     /**
      * Check if the stream is mid-preparing.