diff --git a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
index ec33478..ba40876 100644
--- a/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
+++ b/media/libmediaplayerservice/nuplayer/RTSPSource.cpp
@@ -32,6 +32,12 @@
 
 const int64_t kNearEOSTimeoutUs = 2000000ll; // 2 secs
 
+// Buffer Underflow/Prepare/StartServer/Overflow Marks
+const int64_t NuPlayer::RTSPSource::kUnderflowMarkUs   =  1000000ll;
+const int64_t NuPlayer::RTSPSource::kPrepareMarkUs     =  3000000ll;
+const int64_t NuPlayer::RTSPSource::kStartServerMarkUs =  5000000ll;
+const int64_t NuPlayer::RTSPSource::kOverflowMarkUs    = 10000000ll;
+
 NuPlayer::RTSPSource::RTSPSource(
         const sp<AMessage> &notify,
         const sp<IMediaHTTPService> &httpService,
@@ -51,6 +57,7 @@
       mFinalResult(OK),
       mDisconnectReplyID(0),
       mBuffering(false),
+      mInPreparationPhase(true),
       mSeekGeneration(0),
       mEOSTimeoutAudio(0),
       mEOSTimeoutVideo(0) {
@@ -127,29 +134,6 @@
     msg->postAndAwaitResponse(&dummy);
 }
 
-void NuPlayer::RTSPSource::pause() {
-    int64_t mediaDurationUs = 0;
-    getDuration(&mediaDurationUs);
-    for (size_t index = 0; index < mTracks.size(); index++) {
-        TrackInfo *info = &mTracks.editItemAt(index);
-        sp<AnotherPacketSource> source = info->mSource;
-
-        // Check if EOS or ERROR is received
-        if (source != NULL && source->isFinished(mediaDurationUs)) {
-            return;
-        }
-    }
-    if (mHandler != NULL) {
-        mHandler->pause();
-    }
-}
-
-void NuPlayer::RTSPSource::resume() {
-    if (mHandler != NULL) {
-        mHandler->resume();
-    }
-}
-
 status_t NuPlayer::RTSPSource::feedMoreTSData() {
     Mutex::Autolock _l(mBufferingLock);
     return mFinalResult;
@@ -324,6 +308,73 @@
     mHandler->seek(seekTimeUs);
 }
 
+void NuPlayer::RTSPSource::schedulePollBuffering() {
+    sp<AMessage> msg = new AMessage(kWhatPollBuffering, this);
+    msg->post(1000000ll); // 1 second intervals
+}
+
+void NuPlayer::RTSPSource::checkBuffering(
+        bool *prepared, bool *underflow, bool *overflow, bool *startServer) {
+    size_t numTracks = mTracks.size();
+    size_t preparedCount, underflowCount, overflowCount, startCount;
+    preparedCount = underflowCount = overflowCount = startCount = 0;
+    for (size_t i = 0; i < numTracks; ++i) {
+        status_t finalResult;
+        TrackInfo *info = &mTracks.editItemAt(i);
+        sp<AnotherPacketSource> src = info->mSource;
+        int64_t bufferedDurationUs = src->getBufferedDurationUs(&finalResult);
+
+        // isFinished when duration is 0 checks for EOS result only
+        if (bufferedDurationUs > kPrepareMarkUs || src->isFinished(/* duration */ 0)) {
+            ++preparedCount;
+        }
+
+        if (src->isFinished(/* duration */ 0)) {
+            ++overflowCount;
+        } else {
+            if (bufferedDurationUs < kUnderflowMarkUs) {
+                ++underflowCount;
+            }
+            if (bufferedDurationUs > kOverflowMarkUs) {
+                ++overflowCount;
+            }
+            if (bufferedDurationUs < kStartServerMarkUs) {
+                ++startCount;
+            }
+        }
+    }
+
+    *prepared    = (preparedCount == numTracks);
+    *underflow   = (underflowCount > 0);
+    *overflow    = (overflowCount == numTracks);
+    *startServer = (startCount > 0);
+}
+
+void NuPlayer::RTSPSource::onPollBuffering() {
+    bool prepared, underflow, overflow, startServer;
+    checkBuffering(&prepared, &underflow, &overflow, &startServer);
+
+    if (prepared && mInPreparationPhase) {
+        mInPreparationPhase = false;
+        notifyPrepared();
+    }
+
+    if (!mInPreparationPhase && underflow) {
+        startBufferingIfNecessary();
+    }
+
+    if (overflow && mHandler != NULL) {
+        stopBufferingIfNecessary();
+        mHandler->pause();
+    }
+
+    if (startServer && mHandler != NULL) {
+        mHandler->resume();
+    }
+
+    schedulePollBuffering();
+}
+
 void NuPlayer::RTSPSource::onMessageReceived(const sp<AMessage> &msg) {
     if (msg->what() == kWhatDisconnect) {
         sp<AReplyToken> replyID;
@@ -348,6 +399,9 @@
 
         performSeek(seekTimeUs);
         return;
+    } else if (msg->what() == kWhatPollBuffering) {
+        onPollBuffering();
+        return;
     }
 
     CHECK_EQ(msg->what(), (int)kWhatNotify);
@@ -372,7 +426,7 @@
             }
 
             notifyFlagsChanged(flags);
-            notifyPrepared();
+            schedulePollBuffering();
             break;
         }
 
diff --git a/media/libmediaplayerservice/nuplayer/RTSPSource.h b/media/libmediaplayerservice/nuplayer/RTSPSource.h
index 6438a1e..a6a7644 100644
--- a/media/libmediaplayerservice/nuplayer/RTSPSource.h
+++ b/media/libmediaplayerservice/nuplayer/RTSPSource.h
@@ -43,8 +43,6 @@
     virtual void prepareAsync();
     virtual void start();
     virtual void stop();
-    virtual void pause();
-    virtual void resume();
 
     virtual status_t feedMoreTSData();
 
@@ -65,6 +63,7 @@
         kWhatNotify          = 'noti',
         kWhatDisconnect      = 'disc',
         kWhatPerformSeek     = 'seek',
+        kWhatPollBuffering   = 'poll',
     };
 
     enum State {
@@ -79,6 +78,12 @@
         kFlagIncognito = 1,
     };
 
+    // Buffer Prepare/Underflow/Overflow/Resume Marks
+    static const int64_t kPrepareMarkUs;
+    static const int64_t kUnderflowMarkUs;
+    static const int64_t kOverflowMarkUs;
+    static const int64_t kStartServerMarkUs;
+
     struct TrackInfo {
         sp<AnotherPacketSource> mSource;
 
@@ -100,6 +105,7 @@
     sp<AReplyToken> mDisconnectReplyID;
     Mutex mBufferingLock;
     bool mBuffering;
+    bool mInPreparationPhase;
 
     sp<ALooper> mLooper;
     sp<MyHandler> mHandler;
@@ -126,6 +132,9 @@
     void finishDisconnectIfPossible();
 
     void performSeek(int64_t seekTimeUs);
+    void schedulePollBuffering();
+    void checkBuffering(bool *prepared, bool *underflow, bool *overflow, bool *startServer);
+    void onPollBuffering();
 
     bool haveSufficientDataOnAllTracks();
 
diff --git a/media/libstagefright/rtsp/MyHandler.h b/media/libstagefright/rtsp/MyHandler.h
index eedbb42..6fa83fa 100644
--- a/media/libstagefright/rtsp/MyHandler.h
+++ b/media/libstagefright/rtsp/MyHandler.h
@@ -235,7 +235,7 @@
         sp<AMessage> msg = new AMessage('paus', this);
         mPauseGeneration++;
         msg->setInt32("pausecheck", mPauseGeneration);
-        msg->post(kPauseDelayUs);
+        msg->post();
     }
 
     void resume() {
@@ -979,6 +979,11 @@
 
             case 'accu':
             {
+                if (mSeekPending) {
+                    ALOGV("Stale access unit.");
+                    break;
+                }
+
                 int32_t timeUpdate;
                 if (msg->findInt32("time-update", &timeUpdate) && timeUpdate) {
                     size_t trackIndex;
@@ -1070,6 +1075,12 @@
                     ALOGW("This is a live stream, ignoring pause request.");
                     break;
                 }
+
+                if (mPausing) {
+                    ALOGV("This stream is already paused.");
+                    break;
+                }
+
                 mCheckPending = true;
                 ++mCheckGeneration;
                 mPausing = true;