diff --git a/include/media/stagefright/SurfaceMediaSource.h b/include/media/stagefright/SurfaceMediaSource.h
index 9e07ea4..f60a535 100644
--- a/include/media/stagefright/SurfaceMediaSource.h
+++ b/include/media/stagefright/SurfaceMediaSource.h
@@ -52,6 +52,8 @@
 // may be dropped.  It is possible to wait for the buffers to be
 // returned (but not implemented)
 
+#define DEBUG_PENDING_BUFFERS   0
+
 class SurfaceMediaSource : public MediaSource,
                                 public MediaBufferObserver,
                                 protected BufferQueue::ConsumerListener {
@@ -169,6 +171,10 @@
 
     size_t mNumPendingBuffers;
 
+#if DEBUG_PENDING_BUFFERS
+    Vector<MediaBuffer *> mPendingBuffers;
+#endif
+
     // mCurrentTimestamp is the timestamp for the current texture. It
     // gets set to mLastQueuedTimestamp each time updateTexImage is called.
     int64_t mCurrentTimestamp;
diff --git a/media/libstagefright/ACodec.cpp b/media/libstagefright/ACodec.cpp
index 8190498..2b4220f 100644
--- a/media/libstagefright/ACodec.cpp
+++ b/media/libstagefright/ACodec.cpp
@@ -32,6 +32,8 @@
 #include <media/stagefright/OMXClient.h>
 #include <media/stagefright/OMXCodec.h>
 
+#include <media/hardware/HardwareAPI.h>
+
 #include <OMX_Component.h>
 
 #include "include/avc_utils.h"
@@ -881,6 +883,33 @@
         }
     }
 
+    int32_t prependSPSPPS;
+    if (encoder
+            && msg->findInt32("prepend-sps-pps-to-idr-frames", &prependSPSPPS)
+            && prependSPSPPS != 0) {
+        OMX_INDEXTYPE index;
+        err = mOMX->getExtensionIndex(
+                mNode,
+                "OMX.google.android.index.prependSPSPPSToIDRFrames",
+                &index);
+
+        if (err == OK) {
+            PrependSPSPPSToIDRFramesParams params;
+            InitOMXParams(&params);
+            params.bEnable = OMX_TRUE;
+
+            err = mOMX->setParameter(
+                    mNode, index, &params, sizeof(params));
+        }
+
+        if (err != OK) {
+            ALOGE("Encoder could not be configured to emit SPS/PPS before "
+                  "IDR frames. (err %d)", err);
+
+            return err;
+        }
+    }
+
     if (!strncasecmp(mime, "video/", 6)) {
         if (encoder) {
             err = setupVideoEncoder(mime, msg);
@@ -2471,6 +2500,9 @@
         // by this "mediaBuffer" object. Now that the OMX component has
         // told us that it's done with the input buffer, we can decrement
         // the mediaBuffer's reference count.
+
+        ALOGV("releasing mbuf %p", mediaBuffer);
+
         ((MediaBuffer *)mediaBuffer)->release();
         mediaBuffer = NULL;
 
diff --git a/media/libstagefright/SurfaceMediaSource.cpp b/media/libstagefright/SurfaceMediaSource.cpp
index 3d3f421..9d39d0e 100644
--- a/media/libstagefright/SurfaceMediaSource.cpp
+++ b/media/libstagefright/SurfaceMediaSource.cpp
@@ -191,6 +191,23 @@
     ALOGV("stop");
     Mutex::Autolock lock(mMutex);
 
+    if (mStopped) {
+        return OK;
+    }
+
+    while (mNumPendingBuffers > 0) {
+        ALOGI("Still waiting for %d buffers to be returned.",
+                mNumPendingBuffers);
+
+#if DEBUG_PENDING_BUFFERS
+        for (size_t i = 0; i < mPendingBuffers.size(); ++i) {
+            ALOGI("%d: %p", i, mPendingBuffers.itemAt(i));
+        }
+#endif
+
+        mMediaBuffersAvailableCondition.wait(mMutex);
+    }
+
     mStopped = true;
     mFrameAvailableCondition.signal();
     mMediaBuffersAvailableCondition.signal();
@@ -335,6 +352,12 @@
 
     ++mNumPendingBuffers;
 
+#if DEBUG_PENDING_BUFFERS
+    mPendingBuffers.push_back(*buffer);
+#endif
+
+    ALOGV("returning mbuf %p", *buffer);
+
     return OK;
 }
 
@@ -391,6 +414,15 @@
         CHECK(!"signalBufferReturned: bogus buffer");
     }
 
+#if DEBUG_PENDING_BUFFERS
+    for (size_t i = 0; i < mPendingBuffers.size(); ++i) {
+        if (mPendingBuffers.itemAt(i) == buffer) {
+            mPendingBuffers.removeAt(i);
+            break;
+        }
+    }
+#endif
+
     --mNumPendingBuffers;
     mMediaBuffersAvailableCondition.broadcast();
 }
diff --git a/media/libstagefright/wifi-display/ANetworkSession.cpp b/media/libstagefright/wifi-display/ANetworkSession.cpp
index 90db758..0279c34 100644
--- a/media/libstagefright/wifi-display/ANetworkSession.cpp
+++ b/media/libstagefright/wifi-display/ANetworkSession.cpp
@@ -176,7 +176,7 @@
 }
 
 ANetworkSession::Session::~Session() {
-    ALOGI("Session %d gone", mSessionID);
+    ALOGV("Session %d gone", mSessionID);
 
     close(mSocket);
     mSocket = -1;
@@ -1084,7 +1084,7 @@
                 } else {
                     status_t err = session->readMore();
                     if (err != OK) {
-                        ALOGI("readMore on socket %d failed w/ error %d (%s)",
+                        ALOGE("readMore on socket %d failed w/ error %d (%s)",
                               s, err, strerror(-err));
                     }
                 }
@@ -1093,7 +1093,7 @@
             if (FD_ISSET(s, &ws)) {
                 status_t err = session->writeMore();
                 if (err != OK) {
-                    ALOGI("writeMore on socket %d failed w/ error %d (%s)",
+                    ALOGE("writeMore on socket %d failed w/ error %d (%s)",
                           s, err, strerror(-err));
                 }
             }
diff --git a/media/libstagefright/wifi-display/source/Converter.cpp b/media/libstagefright/wifi-display/source/Converter.cpp
index c6118d4..968a805 100644
--- a/media/libstagefright/wifi-display/source/Converter.cpp
+++ b/media/libstagefright/wifi-display/source/Converter.cpp
@@ -20,12 +20,15 @@
 
 #include "Converter.h"
 
+#include "MediaPuller.h"
+
 #include <cutils/properties.h>
 #include <gui/SurfaceTextureClient.h>
 #include <media/ICrypto.h>
 #include <media/stagefright/foundation/ABuffer.h>
 #include <media/stagefright/foundation/ADebug.h>
 #include <media/stagefright/foundation/AMessage.h>
+#include <media/stagefright/MediaBuffer.h>
 #include <media/stagefright/MediaCodec.h>
 #include <media/stagefright/MediaDefs.h>
 #include <media/stagefright/MediaErrors.h>
@@ -50,17 +53,22 @@
     }
 
     mInitCheck = initEncoder();
+
+    if (mInitCheck != OK) {
+        if (mEncoder != NULL) {
+            mEncoder->release();
+            mEncoder.clear();
+        }
+    }
 }
 
 Converter::~Converter() {
-    if (mEncoder != NULL) {
-        mEncoder->release();
-        mEncoder.clear();
-    }
+    CHECK(mEncoder == NULL);
+}
 
-    AString mime;
-    CHECK(mInputFormat->findString("mime", &mime));
-    ALOGI("encoder (%s) shut down.", mime.c_str());
+void Converter::shutdownAsync() {
+    ALOGV("shutdown");
+    (new AMessage(kWhatShutdown, id()))->post();
 }
 
 status_t Converter::initCheck() const {
@@ -126,6 +134,7 @@
         mOutputFormat->setInt32("bitrate", videoBitrate);
         mOutputFormat->setInt32("frame-rate", 24);
         mOutputFormat->setInt32("i-frame-interval", 1);  // Iframes every 1 secs
+        // mOutputFormat->setInt32("prepend-sps-pps-to-idr-frames", 1);
     }
 
     ALOGV("output format is '%s'", mOutputFormat->debugString(0).c_str());
@@ -155,16 +164,6 @@
     return mEncoder->getOutputBuffers(&mEncoderOutputBuffers);
 }
 
-void Converter::feedAccessUnit(const sp<ABuffer> &accessUnit) {
-    sp<AMessage> msg = new AMessage(kWhatFeedAccessUnit, id());
-    msg->setBuffer("accessUnit", accessUnit);
-    msg->post();
-}
-
-void Converter::signalEOS() {
-    (new AMessage(kWhatInputEOS, id()))->post();
-}
-
 void Converter::notifyError(status_t err) {
     sp<AMessage> notify = mNotify->dup();
     notify->setInt32("what", kWhatError);
@@ -174,32 +173,70 @@
 
 void Converter::onMessageReceived(const sp<AMessage> &msg) {
     switch (msg->what()) {
-        case kWhatFeedAccessUnit:
+        case kWhatMediaPullerNotify:
         {
-            sp<ABuffer> accessUnit;
-            CHECK(msg->findBuffer("accessUnit", &accessUnit));
+            int32_t what;
+            CHECK(msg->findInt32("what", &what));
 
-            mInputBufferQueue.push_back(accessUnit);
+            if (mEncoder == NULL) {
+                ALOGV("got msg '%s' after encoder shutdown.",
+                      msg->debugString().c_str());
 
-            feedEncoderInputBuffers();
+                if (what == MediaPuller::kWhatAccessUnit) {
+                    sp<ABuffer> accessUnit;
+                    CHECK(msg->findBuffer("accessUnit", &accessUnit));
 
-            scheduleDoMoreWork();
-            break;
-        }
+                    void *mbuf;
+                    if (accessUnit->meta()->findPointer("mediaBuffer", &mbuf)
+                            && mbuf != NULL) {
+                        ALOGV("releasing mbuf %p", mbuf);
 
-        case kWhatInputEOS:
-        {
-            mInputBufferQueue.push_back(NULL);
+                        accessUnit->meta()->setPointer("mediaBuffer", NULL);
 
-            feedEncoderInputBuffers();
+                        static_cast<MediaBuffer *>(mbuf)->release();
+                        mbuf = NULL;
+                    }
+                }
+                break;
+            }
 
-            scheduleDoMoreWork();
+            if (what == MediaPuller::kWhatEOS) {
+                mInputBufferQueue.push_back(NULL);
+
+                feedEncoderInputBuffers();
+
+                scheduleDoMoreWork();
+            } else {
+                CHECK_EQ(what, MediaPuller::kWhatAccessUnit);
+
+                sp<ABuffer> accessUnit;
+                CHECK(msg->findBuffer("accessUnit", &accessUnit));
+
+#if 0
+                void *mbuf;
+                if (accessUnit->meta()->findPointer("mediaBuffer", &mbuf)
+                        && mbuf != NULL) {
+                    ALOGI("queueing mbuf %p", mbuf);
+                }
+#endif
+
+                mInputBufferQueue.push_back(accessUnit);
+
+                feedEncoderInputBuffers();
+
+                scheduleDoMoreWork();
+            }
             break;
         }
 
         case kWhatDoMoreWork:
         {
             mDoMoreWorkPending = false;
+
+            if (mEncoder == NULL) {
+                break;
+            }
+
             status_t err = doMoreWork();
 
             if (err != OK) {
@@ -212,6 +249,10 @@
 
         case kWhatRequestIDRFrame:
         {
+            if (mEncoder == NULL) {
+                break;
+            }
+
             if (mIsVideo) {
                 ALOGI("requesting IDR frame");
                 mEncoder->requestIDRFrame();
@@ -219,6 +260,18 @@
             break;
         }
 
+        case kWhatShutdown:
+        {
+            ALOGI("shutting down encoder");
+            mEncoder->release();
+            mEncoder.clear();
+
+            AString mime;
+            CHECK(mInputFormat->findString("mime", &mime));
+            ALOGI("encoder (%s) shut down.", mime.c_str());
+            break;
+        }
+
         default:
             TRESPASS();
     }
diff --git a/media/libstagefright/wifi-display/source/Converter.h b/media/libstagefright/wifi-display/source/Converter.h
index 901ae2e..9f54523 100644
--- a/media/libstagefright/wifi-display/source/Converter.h
+++ b/media/libstagefright/wifi-display/source/Converter.h
@@ -51,18 +51,20 @@
         kWhatError,
     };
 
+    enum {
+        kWhatDoMoreWork,
+        kWhatRequestIDRFrame,
+        kWhatShutdown,
+        kWhatMediaPullerNotify,
+    };
+
+    void shutdownAsync();
+
 protected:
     virtual ~Converter();
     virtual void onMessageReceived(const sp<AMessage> &msg);
 
 private:
-    enum {
-        kWhatFeedAccessUnit,
-        kWhatInputEOS,
-        kWhatDoMoreWork,
-        kWhatRequestIDRFrame,
-    };
-
     status_t mInitCheck;
     sp<AMessage> mNotify;
     sp<ALooper> mCodecLooper;
diff --git a/media/libstagefright/wifi-display/source/MediaPuller.cpp b/media/libstagefright/wifi-display/source/MediaPuller.cpp
index 35ae539..82ae001 100644
--- a/media/libstagefright/wifi-display/source/MediaPuller.cpp
+++ b/media/libstagefright/wifi-display/source/MediaPuller.cpp
@@ -65,33 +65,20 @@
     return postSynchronouslyAndReturnError(new AMessage(kWhatStart, id()));
 }
 
-status_t MediaPuller::stop() {
-    return postSynchronouslyAndReturnError(new AMessage(kWhatStop, id()));
+void MediaPuller::stopAsync(const sp<AMessage> &notify) {
+    sp<AMessage> msg = new AMessage(kWhatStop, id());
+    msg->setMessage("notify", notify);
+    msg->post();
 }
 
 void MediaPuller::onMessageReceived(const sp<AMessage> &msg) {
     switch (msg->what()) {
         case kWhatStart:
-        case kWhatStop:
         {
-            status_t err;
+            status_t err = mSource->start();
 
-            if (msg->what() == kWhatStart) {
-                err = mSource->start();
-
-                if (err == OK) {
-                    schedulePull();
-                }
-            } else {
-                sp<MetaData> meta = mSource->getFormat();
-                const char *tmp;
-                CHECK(meta->findCString(kKeyMIMEType, &tmp));
-                AString mime = tmp;
-
-                ALOGI("MediaPuller(%s) stopping.", mime.c_str());
-                err = mSource->stop();
-                ALOGI("MediaPuller(%s) stopped.", mime.c_str());
-                ++mPullGeneration;
+            if (err == OK) {
+                schedulePull();
             }
 
             sp<AMessage> response = new AMessage;
@@ -104,6 +91,24 @@
             break;
         }
 
+        case kWhatStop:
+        {
+            sp<MetaData> meta = mSource->getFormat();
+            const char *tmp;
+            CHECK(meta->findCString(kKeyMIMEType, &tmp));
+            AString mime = tmp;
+
+            ALOGI("MediaPuller(%s) stopping.", mime.c_str());
+            mSource->stop();
+            ALOGI("MediaPuller(%s) stopped.", mime.c_str());
+            ++mPullGeneration;
+
+            sp<AMessage> notify;
+            CHECK(msg->findMessage("notify", &notify));
+            notify->post();
+            break;
+        }
+
         case kWhatPull:
         {
             int32_t generation;
@@ -153,6 +158,10 @@
                 notify->setBuffer("accessUnit", accessUnit);
                 notify->post();
 
+                if (mbuf != NULL) {
+                    ALOGV("posted mbuf %p", mbuf);
+                }
+
                 schedulePull();
             }
             break;
diff --git a/media/libstagefright/wifi-display/source/MediaPuller.h b/media/libstagefright/wifi-display/source/MediaPuller.h
index 134e1c0..728da7b 100644
--- a/media/libstagefright/wifi-display/source/MediaPuller.h
+++ b/media/libstagefright/wifi-display/source/MediaPuller.h
@@ -33,7 +33,7 @@
     MediaPuller(const sp<MediaSource> &source, const sp<AMessage> &notify);
 
     status_t start();
-    status_t stop();
+    void stopAsync(const sp<AMessage> &notify);
 
 protected:
     virtual void onMessageReceived(const sp<AMessage> &msg);
diff --git a/media/libstagefright/wifi-display/source/PlaybackSession.cpp b/media/libstagefright/wifi-display/source/PlaybackSession.cpp
index 0facafe..775f23b 100644
--- a/media/libstagefright/wifi-display/source/PlaybackSession.cpp
+++ b/media/libstagefright/wifi-display/source/PlaybackSession.cpp
@@ -53,14 +53,17 @@
 static size_t kMaxRTPPacketSize = 1500;
 static size_t kMaxNumTSPacketsPerRTPPacket = (kMaxRTPPacketSize - 12) / 188;
 
-struct WifiDisplaySource::PlaybackSession::Track : public RefBase {
-    Track(const sp<ALooper> &pullLooper,
+struct WifiDisplaySource::PlaybackSession::Track : public AHandler {
+    enum {
+        kWhatStopped,
+    };
+
+    Track(const sp<AMessage> &notify,
+          const sp<ALooper> &pullLooper,
           const sp<ALooper> &codecLooper,
           const sp<MediaPuller> &mediaPuller,
           const sp<Converter> &converter);
 
-    Track(const sp<AMessage> &format);
-
     sp<AMessage> getFormat();
     bool isAudio() const;
 
@@ -70,20 +73,27 @@
     void setPacketizerTrackIndex(size_t index);
 
     status_t start();
-    status_t stop();
+    void stopAsync();
+
+    bool isStopped() const { return !mStarted; }
 
     void queueAccessUnit(const sp<ABuffer> &accessUnit);
     sp<ABuffer> dequeueAccessUnit();
 
 protected:
+    virtual void onMessageReceived(const sp<AMessage> &msg);
     virtual ~Track();
 
 private:
+    enum {
+        kWhatMediaPullerStopped,
+    };
+
+    sp<AMessage> mNotify;
     sp<ALooper> mPullLooper;
     sp<ALooper> mCodecLooper;
     sp<MediaPuller> mMediaPuller;
     sp<Converter> mConverter;
-    sp<AMessage> mFormat;
     bool mStarted;
     ssize_t mPacketizerTrackIndex;
     bool mIsAudio;
@@ -95,11 +105,13 @@
 };
 
 WifiDisplaySource::PlaybackSession::Track::Track(
+        const sp<AMessage> &notify,
         const sp<ALooper> &pullLooper,
         const sp<ALooper> &codecLooper,
         const sp<MediaPuller> &mediaPuller,
         const sp<Converter> &converter)
-    : mPullLooper(pullLooper),
+    : mNotify(notify),
+      mPullLooper(pullLooper),
       mCodecLooper(codecLooper),
       mMediaPuller(mediaPuller),
       mConverter(converter),
@@ -108,14 +120,8 @@
       mIsAudio(IsAudioFormat(mConverter->getOutputFormat())) {
 }
 
-WifiDisplaySource::PlaybackSession::Track::Track(const sp<AMessage> &format)
-    : mFormat(format),
-      mPacketizerTrackIndex(-1),
-      mIsAudio(IsAudioFormat(mFormat)) {
-}
-
 WifiDisplaySource::PlaybackSession::Track::~Track() {
-    stop();
+    CHECK(!mStarted);
 }
 
 // static
@@ -128,10 +134,6 @@
 }
 
 sp<AMessage> WifiDisplaySource::PlaybackSession::Track::getFormat() {
-    if (mFormat != NULL) {
-        return mFormat;
-    }
-
     return mConverter->getOutputFormat();
 }
 
@@ -155,9 +157,7 @@
 status_t WifiDisplaySource::PlaybackSession::Track::start() {
     ALOGV("Track::start isAudio=%d", mIsAudio);
 
-    if (mStarted) {
-        return INVALID_OPERATION;
-    }
+    CHECK(!mStarted);
 
     status_t err = OK;
 
@@ -172,24 +172,40 @@
     return err;
 }
 
-status_t WifiDisplaySource::PlaybackSession::Track::stop() {
-    ALOGV("Track::stop isAudio=%d", mIsAudio);
+void WifiDisplaySource::PlaybackSession::Track::stopAsync() {
+    ALOGV("Track::stopAsync isAudio=%d", mIsAudio);
 
-    if (!mStarted) {
-        return INVALID_OPERATION;
-    }
+    CHECK(mStarted);
 
-    status_t err = OK;
+    mConverter->shutdownAsync();
+
+    sp<AMessage> msg = new AMessage(kWhatMediaPullerStopped, id());
 
     if (mMediaPuller != NULL) {
-        err = mMediaPuller->stop();
+        mMediaPuller->stopAsync(msg);
+    } else {
+        msg->post();
     }
+}
 
-    mConverter.clear();
+void WifiDisplaySource::PlaybackSession::Track::onMessageReceived(
+        const sp<AMessage> &msg) {
+    switch (msg->what()) {
+        case kWhatMediaPullerStopped:
+        {
+            mConverter.clear();
 
-    mStarted = false;
+            mStarted = false;
 
-    return err;
+            sp<AMessage> notify = mNotify->dup();
+            notify->setInt32("what", kWhatStopped);
+            notify->post();
+            break;
+        }
+
+        default:
+            TRESPASS();
+    }
 }
 
 void WifiDisplaySource::PlaybackSession::Track::queueAccessUnit(
@@ -482,15 +498,7 @@
     }
 
     for (size_t i = 0; i < mTracks.size(); ++i) {
-        status_t err = mTracks.editValueAt(i)->start();
-
-        if (err != OK) {
-            for (size_t j = 0; j < i; ++j) {
-                mTracks.editValueAt(j)->stop();
-            }
-
-            return err;
-        }
+        CHECK_EQ((status_t)OK, mTracks.editValueAt(i)->start());
     }
 
     sp<AMessage> notify = mNotify->dup();
@@ -506,32 +514,12 @@
     return OK;
 }
 
-status_t WifiDisplaySource::PlaybackSession::destroy() {
-    mTracks.clear();
+void WifiDisplaySource::PlaybackSession::destroyAsync() {
+    ALOGI("destroyAsync");
 
-    mPacketizer.clear();
-
-    mTracks.clear();
-
-#if ENABLE_RETRANSMISSION
-    if (mRTCPRetransmissionSessionID != 0) {
-        mNetSession->destroySession(mRTCPRetransmissionSessionID);
+    for (size_t i = 0; i < mTracks.size(); ++i) {
+        mTracks.valueAt(i)->stopAsync();
     }
-
-    if (mRTPRetransmissionSessionID != 0) {
-        mNetSession->destroySession(mRTPRetransmissionSessionID);
-    }
-#endif
-
-    if (mRTCPSessionID != 0) {
-        mNetSession->destroySession(mRTCPSessionID);
-    }
-
-    if (mRTPSessionID != 0) {
-        mNetSession->destroySession(mRTPSessionID);
-    }
-
-    return OK;
 }
 
 void WifiDisplaySource::PlaybackSession::onMessageReceived(
@@ -669,32 +657,6 @@
             break;
         }
 
-        case kWhatMediaPullerNotify:
-        {
-            int32_t what;
-            CHECK(msg->findInt32("what", &what));
-
-            if (what == MediaPuller::kWhatEOS) {
-                ALOGI("input eos");
-
-                for (size_t i = 0; i < mTracks.size(); ++i) {
-                    mTracks.valueAt(i)->converter()->signalEOS();
-                }
-            } else {
-                CHECK_EQ(what, MediaPuller::kWhatAccessUnit);
-
-                size_t trackIndex;
-                CHECK(msg->findSize("trackIndex", &trackIndex));
-
-                sp<ABuffer> accessUnit;
-                CHECK(msg->findBuffer("accessUnit", &accessUnit));
-
-                mTracks.valueFor(trackIndex)->converter()
-                    ->feedAccessUnit(accessUnit);
-            }
-            break;
-        }
-
         case kWhatConverterNotify:
         {
             int32_t what;
@@ -776,6 +738,57 @@
             break;
         }
 
+        case kWhatTrackNotify:
+        {
+            int32_t what;
+            CHECK(msg->findInt32("what", &what));
+
+            size_t trackIndex;
+            CHECK(msg->findSize("trackIndex", &trackIndex));
+
+            if (what == Track::kWhatStopped) {
+                bool allTracksAreStopped = true;
+                for (size_t i = 0; i < mTracks.size(); ++i) {
+                    const sp<Track> &track = mTracks.valueAt(i);
+                    if (!track->isStopped()) {
+                        allTracksAreStopped = false;
+                        break;
+                    }
+                }
+
+                if (!allTracksAreStopped) {
+                    break;
+                }
+
+                mTracks.clear();
+
+                mPacketizer.clear();
+
+#if ENABLE_RETRANSMISSION
+                if (mRTCPRetransmissionSessionID != 0) {
+                    mNetSession->destroySession(mRTCPRetransmissionSessionID);
+                }
+
+                if (mRTPRetransmissionSessionID != 0) {
+                    mNetSession->destroySession(mRTPRetransmissionSessionID);
+                }
+#endif
+
+                if (mRTCPSessionID != 0) {
+                    mNetSession->destroySession(mRTCPSessionID);
+                }
+
+                if (mRTPSessionID != 0) {
+                    mNetSession->destroySession(mRTPSessionID);
+                }
+
+                sp<AMessage> notify = mNotify->dup();
+                notify->setInt32("what", kWhatSessionDestroyed);
+                notify->post();
+            }
+            break;
+        }
+
         default:
             TRESPASS();
     }
@@ -817,11 +830,6 @@
 
     trackIndex = mTracks.size();
 
-    notify = new AMessage(kWhatMediaPullerNotify, id());
-    notify->setSize("trackIndex", trackIndex);
-    sp<MediaPuller> puller = new MediaPuller(source, notify);
-    pullLooper->registerHandler(puller);
-
     sp<AMessage> format;
     status_t err = convertMetaDataToMessage(source->getFormat(), &format);
     CHECK_EQ(err, (status_t)OK);
@@ -838,15 +846,32 @@
 
     sp<Converter> converter =
         new Converter(notify, codecLooper, format);
-    CHECK_EQ(converter->initCheck(), (status_t)OK);
+
+    if (converter->initCheck() != OK) {
+        return converter->initCheck();
+    }
 
     looper()->registerHandler(converter);
 
+    notify = new AMessage(Converter::kWhatMediaPullerNotify, converter->id());
+    notify->setSize("trackIndex", trackIndex);
+
+    sp<MediaPuller> puller = new MediaPuller(source, notify);
+    pullLooper->registerHandler(puller);
+
     if (numInputBuffers != NULL) {
         *numInputBuffers = converter->getInputBufferCount();
     }
 
-    mTracks.add(trackIndex, new Track(pullLooper, codecLooper, puller, converter));
+    notify = new AMessage(kWhatTrackNotify, id());
+    notify->setSize("trackIndex", trackIndex);
+
+    sp<Track> track = new Track(
+            notify, pullLooper, codecLooper, puller, converter);
+
+    looper()->registerHandler(track);
+
+    mTracks.add(trackIndex, track);
 
     if (isVideo) {
         mVideoTrackIndex = trackIndex;
diff --git a/media/libstagefright/wifi-display/source/PlaybackSession.h b/media/libstagefright/wifi-display/source/PlaybackSession.h
index 342fc85..9237a72 100644
--- a/media/libstagefright/wifi-display/source/PlaybackSession.h
+++ b/media/libstagefright/wifi-display/source/PlaybackSession.h
@@ -51,7 +51,7 @@
             const char *clientIP, int32_t clientRtp, int32_t clientRtcp,
             TransportMode transportMode);
 
-    status_t destroy();
+    void destroyAsync();
 
     int32_t getRTPPort() const;
 
@@ -72,6 +72,7 @@
         kWhatSessionDead,
         kWhatBinaryData,
         kWhatSessionEstablished,
+        kWhatSessionDestroyed,
     };
 
 protected:
@@ -91,6 +92,7 @@
 #endif
         kWhatMediaPullerNotify,
         kWhatConverterNotify,
+        kWhatTrackNotify,
         kWhatUpdateSurface,
         kWhatFinishPlay,
     };
diff --git a/media/libstagefright/wifi-display/source/RepeaterSource.cpp b/media/libstagefright/wifi-display/source/RepeaterSource.cpp
index 56e8860..483d29c 100644
--- a/media/libstagefright/wifi-display/source/RepeaterSource.cpp
+++ b/media/libstagefright/wifi-display/source/RepeaterSource.cpp
@@ -50,6 +50,8 @@
 }
 
 status_t RepeaterSource::stop() {
+    ALOGV("stopping");
+
     if (mLooper != NULL) {
         mLooper->stop();
         mLooper.clear();
@@ -57,7 +59,17 @@
         mReflector.clear();
     }
 
-    return mSource->stop();
+    if (mBuffer != NULL) {
+        ALOGV("releasing mbuf %p", mBuffer);
+        mBuffer->release();
+        mBuffer = NULL;
+    }
+
+    status_t err = mSource->stop();
+
+    ALOGV("stopped");
+
+    return err;
 }
 
 sp<MetaData> RepeaterSource::getFormat() {
@@ -117,6 +129,8 @@
             MediaBuffer *buffer;
             status_t err = mSource->read(&buffer);
 
+            ALOGV("read mbuf %p", buffer);
+
             Mutex::Autolock autoLock(mLock);
             if (mBuffer != NULL) {
                 mBuffer->release();
diff --git a/media/libstagefright/wifi-display/source/WifiDisplaySource.cpp b/media/libstagefright/wifi-display/source/WifiDisplaySource.cpp
index 16c0f35..8091cc4 100644
--- a/media/libstagefright/wifi-display/source/WifiDisplaySource.cpp
+++ b/media/libstagefright/wifi-display/source/WifiDisplaySource.cpp
@@ -293,6 +293,8 @@
                             mClientInfo.mPlaybackSession->height(),
                             0 /* flags */);
                 }
+            } else if (what == PlaybackSession::kWhatSessionDestroyed) {
+                disconnectClient2();
             } else {
                 CHECK_EQ(what, PlaybackSession::kWhatBinaryData);
 
@@ -1117,6 +1119,12 @@
 void WifiDisplaySource::finishStop() {
     ALOGV("finishStop");
 
+    disconnectClientAsync();
+}
+
+void WifiDisplaySource::finishStopAfterDisconnectingClient() {
+    ALOGV("finishStopAfterDisconnectingClient");
+
 #if REQUIRE_HDCP
     if (mHDCP != NULL) {
         ALOGI("Initiating HDCP shutdown.");
@@ -1137,14 +1145,12 @@
     mHDCP.clear();
 #endif
 
-    disconnectClient();
-
     if (mSessionID != 0) {
         mNetSession->destroySession(mSessionID);
         mSessionID = 0;
     }
 
-    ALOGV("finishStop2 completed.");
+    ALOGI("We're stopped.");
 
     status_t err = OK;
 
@@ -1264,14 +1270,26 @@
     return mClientInfo.mPlaybackSession;
 }
 
-void WifiDisplaySource::disconnectClient() {
-    if (mClientInfo.mPlaybackSession != NULL) {
-        sp<PlaybackSession> playbackSession = mClientInfo.mPlaybackSession;
-        mClientInfo.mPlaybackSession.clear();
+void WifiDisplaySource::disconnectClientAsync() {
+    ALOGV("disconnectClient");
 
-        ALOGI("Destroying PlaybackSession");
-        playbackSession->destroy();
-        looper()->unregisterHandler(playbackSession->id());
+    if (mClientInfo.mPlaybackSession == NULL) {
+        disconnectClient2();
+        return;
+    }
+
+    if (mClientInfo.mPlaybackSession != NULL) {
+        ALOGV("Destroying PlaybackSession");
+        mClientInfo.mPlaybackSession->destroyAsync();
+    }
+}
+
+void WifiDisplaySource::disconnectClient2() {
+    ALOGV("disconnectClient2");
+
+    if (mClientInfo.mPlaybackSession != NULL) {
+        looper()->unregisterHandler(mClientInfo.mPlaybackSession->id());
+        mClientInfo.mPlaybackSession.clear();
     }
 
     if (mClientSessionID != 0) {
@@ -1280,6 +1298,8 @@
     }
 
     mClient->onDisplayDisconnected();
+
+    finishStopAfterDisconnectingClient();
 }
 
 #if REQUIRE_HDCP
diff --git a/media/libstagefright/wifi-display/source/WifiDisplaySource.h b/media/libstagefright/wifi-display/source/WifiDisplaySource.h
index 77b15f8..ade623a 100644
--- a/media/libstagefright/wifi-display/source/WifiDisplaySource.h
+++ b/media/libstagefright/wifi-display/source/WifiDisplaySource.h
@@ -200,11 +200,10 @@
     sp<PlaybackSession> findPlaybackSession(
             const sp<ParsedMessage> &data, int32_t *playbackSessionID) const;
 
-    // Disconnects the current client and shuts down its playback session
-    // (if any).
-    void disconnectClient();
-
     void finishStop();
+    void disconnectClientAsync();
+    void disconnectClient2();
+    void finishStopAfterDisconnectingClient();
     void finishStop2();
 
     DISALLOW_EVIL_CONSTRUCTORS(WifiDisplaySource);
diff --git a/services/camera/libcameraservice/Camera2Client.cpp b/services/camera/libcameraservice/Camera2Client.cpp
index a83977f..d315abb 100644
--- a/services/camera/libcameraservice/Camera2Client.cpp
+++ b/services/camera/libcameraservice/Camera2Client.cpp
@@ -624,7 +624,13 @@
 status_t Camera2Client::startPreviewL(Parameters &params, bool restart) {
     ATRACE_CALL();
     status_t res;
-    if (params.state >= Parameters::PREVIEW && !restart) {
+    if (params.state == Parameters::PREVIEW && !restart) {
+        // Succeed attempt to re-enter preview state
+        ALOGI("%s: Not starting preview; already in preview state.",
+              __FUNCTION__);
+        return OK;
+    }
+    if (params.state > Parameters::PREVIEW && !restart) {
         ALOGE("%s: Can't start preview in state %s",
                 __FUNCTION__,
                 Parameters::getStateName(params.state));