diff --git a/include/media/stagefright/NuMediaExtractor.h b/include/media/stagefright/NuMediaExtractor.h
index 9c61113..d46ce36 100644
--- a/include/media/stagefright/NuMediaExtractor.h
+++ b/include/media/stagefright/NuMediaExtractor.h
@@ -28,6 +28,7 @@
 
 struct ABuffer;
 struct AMessage;
+struct DataSource;
 struct MediaBuffer;
 struct MediaExtractor;
 struct MediaSource;
@@ -60,6 +61,8 @@
     status_t getSampleTime(int64_t *sampleTimeUs);
     status_t getSampleMeta(sp<MetaData> *sampleMeta);
 
+    bool getCachedDuration(int64_t *durationUs, bool *eos) const;
+
 protected:
     virtual ~NuMediaExtractor();
 
@@ -78,13 +81,21 @@
         uint32_t mTrackFlags;  // bitmask of "TrackFlags"
     };
 
+    sp<DataSource> mDataSource;
+
     sp<MediaExtractor> mImpl;
+    bool mIsWidevineExtractor;
 
     Vector<TrackInfo> mSelectedTracks;
+    int64_t mTotalBitrate;  // in bits/sec
+    int64_t mDurationUs;
 
     ssize_t fetchTrackSamples(int64_t seekTimeUs = -1ll);
     void releaseTrackSamples();
 
+    bool getTotalBitrate(int64_t *bitRate) const;
+    void updateDurationAndBitrate();
+
     DISALLOW_EVIL_CONSTRUCTORS(NuMediaExtractor);
 };
 
diff --git a/media/libstagefright/NuCachedSource2.cpp b/media/libstagefright/NuCachedSource2.cpp
index 0957426..f1075b1 100644
--- a/media/libstagefright/NuCachedSource2.cpp
+++ b/media/libstagefright/NuCachedSource2.cpp
@@ -501,12 +501,12 @@
     return mCacheOffset + mCache->totalSize();
 }
 
-size_t NuCachedSource2::approxDataRemaining(status_t *finalStatus) {
+size_t NuCachedSource2::approxDataRemaining(status_t *finalStatus) const {
     Mutex::Autolock autoLock(mLock);
     return approxDataRemaining_l(finalStatus);
 }
 
-size_t NuCachedSource2::approxDataRemaining_l(status_t *finalStatus) {
+size_t NuCachedSource2::approxDataRemaining_l(status_t *finalStatus) const {
     *finalStatus = mFinalStatus;
 
     if (mFinalStatus != OK && mNumRetriesLeft > 0) {
diff --git a/media/libstagefright/NuMediaExtractor.cpp b/media/libstagefright/NuMediaExtractor.cpp
index 00bb74f..123e510 100644
--- a/media/libstagefright/NuMediaExtractor.cpp
+++ b/media/libstagefright/NuMediaExtractor.cpp
@@ -21,6 +21,7 @@
 #include <media/stagefright/NuMediaExtractor.h>
 
 #include "include/ESDS.h"
+#include "include/NuCachedSource2.h"
 #include "include/WVMExtractor.h"
 
 #include <media/stagefright/foundation/ABuffer.h>
@@ -38,7 +39,10 @@
 
 namespace android {
 
-NuMediaExtractor::NuMediaExtractor() {
+NuMediaExtractor::NuMediaExtractor()
+    : mIsWidevineExtractor(false),
+      mTotalBitrate(-1ll),
+      mDurationUs(-1ll) {
 }
 
 NuMediaExtractor::~NuMediaExtractor() {
@@ -66,6 +70,7 @@
         return -ENOENT;
     }
 
+    mIsWidevineExtractor = false;
     if (!strncasecmp("widevine://", path, 11)) {
         String8 mimeType;
         float confidence;
@@ -82,6 +87,7 @@
         extractor->setAdaptiveStreamingMode(true);
 
         mImpl = extractor;
+        mIsWidevineExtractor = true;
     } else {
         mImpl = MediaExtractor::Create(dataSource);
     }
@@ -90,6 +96,10 @@
         return ERROR_UNSUPPORTED;
     }
 
+    mDataSource = dataSource;
+
+    updateDurationAndBitrate();
+
     return OK;
 }
 
@@ -111,9 +121,39 @@
         return ERROR_UNSUPPORTED;
     }
 
+    mDataSource = fileSource;
+
+    updateDurationAndBitrate();
+
     return OK;
 }
 
+void NuMediaExtractor::updateDurationAndBitrate() {
+    mTotalBitrate = 0ll;
+    mDurationUs = -1ll;
+
+    for (size_t i = 0; i < mImpl->countTracks(); ++i) {
+        sp<MetaData> meta = mImpl->getTrackMetaData(i);
+
+        int32_t bitrate;
+        if (!meta->findInt32(kKeyBitRate, &bitrate)) {
+            const char *mime;
+            CHECK(meta->findCString(kKeyMIMEType, &mime));
+            ALOGV("track of type '%s' does not publish bitrate", mime);
+
+            mTotalBitrate = -1ll;
+        } else if (mTotalBitrate >= 0ll) {
+            mTotalBitrate += bitrate;
+        }
+
+        int64_t durationUs;
+        if (meta->findInt64(kKeyDuration, &durationUs)
+                && durationUs > mDurationUs) {
+            mDurationUs = durationUs;
+        }
+    }
+}
+
 size_t NuMediaExtractor::countTracks() const {
     return mImpl == NULL ? 0 : mImpl->countTracks();
 }
@@ -508,4 +548,48 @@
     return OK;
 }
 
+bool NuMediaExtractor::getTotalBitrate(int64_t *bitrate) const {
+    if (mTotalBitrate >= 0) {
+        *bitrate = mTotalBitrate;
+        return true;
+    }
+
+    off64_t size;
+    if (mDurationUs >= 0 && mDataSource->getSize(&size) == OK) {
+        *bitrate = size * 8000000ll / mDurationUs;  // in bits/sec
+        return true;
+    }
+
+    return false;
+}
+
+// Returns true iff cached duration is available/applicable.
+bool NuMediaExtractor::getCachedDuration(
+        int64_t *durationUs, bool *eos) const {
+    int64_t bitrate;
+    if (mIsWidevineExtractor) {
+        sp<WVMExtractor> wvmExtractor =
+            static_cast<WVMExtractor *>(mImpl.get());
+
+        status_t finalStatus;
+        *durationUs = wvmExtractor->getCachedDurationUs(&finalStatus);
+        *eos = (finalStatus != OK);
+        return true;
+    } else if ((mDataSource->flags() & DataSource::kIsCachingDataSource)
+            && getTotalBitrate(&bitrate)) {
+        sp<NuCachedSource2> cachedSource =
+            static_cast<NuCachedSource2 *>(mDataSource.get());
+
+        status_t finalStatus;
+        size_t cachedDataRemaining =
+            cachedSource->approxDataRemaining(&finalStatus);
+
+        *durationUs = cachedDataRemaining * 8000000ll / bitrate;
+        *eos = (finalStatus != OK);
+        return true;
+    }
+
+    return false;
+}
+
 }  // namespace android
diff --git a/media/libstagefright/include/NuCachedSource2.h b/media/libstagefright/include/NuCachedSource2.h
index c27a29b..5db4b4b 100644
--- a/media/libstagefright/include/NuCachedSource2.h
+++ b/media/libstagefright/include/NuCachedSource2.h
@@ -49,7 +49,7 @@
     ////////////////////////////////////////////////////////////////////////////
 
     size_t cachedSize();
-    size_t approxDataRemaining(status_t *finalStatus);
+    size_t approxDataRemaining(status_t *finalStatus) const;
 
     void resumeFetchingIfNecessary();
 
@@ -94,7 +94,7 @@
     sp<ALooper> mLooper;
 
     Mutex mSerializer;
-    Mutex mLock;
+    mutable Mutex mLock;
     Condition mCondition;
 
     PageCache *mCache;
@@ -123,7 +123,7 @@
     ssize_t readInternal(off64_t offset, void *data, size_t size);
     status_t seekInternal_l(off64_t offset);
 
-    size_t approxDataRemaining_l(status_t *finalStatus);
+    size_t approxDataRemaining_l(status_t *finalStatus) const;
 
     void restartPrefetcherIfNecessary_l(
             bool ignoreLowWaterThreshold = false, bool force = false);