diff --git a/media/extractors/mp4/MPEG4Extractor.cpp b/media/extractors/mp4/MPEG4Extractor.cpp
index 8412812..d10d0d6 100644
--- a/media/extractors/mp4/MPEG4Extractor.cpp
+++ b/media/extractors/mp4/MPEG4Extractor.cpp
@@ -68,6 +68,7 @@
 };
 
 class MPEG4Source : public MediaTrack {
+static const size_t  kMaxPcmFrameSize = 8192;
 public:
     // Caller retains ownership of both "dataSource" and "sampleTable".
     MPEG4Source(MetaDataBase &format,
@@ -127,7 +128,7 @@
     bool mIsAVC;
     bool mIsHEVC;
     bool mIsAC4;
-
+    bool mIsPcm;
     size_t mNALLengthSize;
 
     bool mStarted;
@@ -329,6 +330,11 @@
             return MEDIA_MIMETYPE_VIDEO_HEVC;
         case FOURCC('a', 'c', '-', '4'):
             return MEDIA_MIMETYPE_AUDIO_AC4;
+
+        case FOURCC('t', 'w', 'o', 's'):
+        case FOURCC('s', 'o', 'w', 't'):
+            return MEDIA_MIMETYPE_AUDIO_RAW;
+
         default:
             ALOGW("Unknown fourcc: %c%c%c%c",
                    (fourcc >> 24) & 0xff,
@@ -1478,6 +1484,8 @@
         case FOURCC('e', 'n', 'c', 'a'):
         case FOURCC('s', 'a', 'm', 'r'):
         case FOURCC('s', 'a', 'w', 'b'):
+        case FOURCC('t', 'w', 'o', 's'):
+        case FOURCC('s', 'o', 'w', 't'):
         {
             if (mIsQT && chunk_type == FOURCC('m', 'p', '4', 'a')
                     && depth >= 1 && mPath[depth - 1] == FOURCC('w', 'a', 'v', 'e')) {
@@ -1547,6 +1555,13 @@
                 // if the chunk type is enca, we'll get the type from the frma box later
                 mLastTrack->meta.setCString(kKeyMIMEType, FourCC2MIME(chunk_type));
                 AdjustChannelsAndRate(chunk_type, &num_channels, &sample_rate);
+
+                if (!strcasecmp(MEDIA_MIMETYPE_AUDIO_RAW, FourCC2MIME(chunk_type))) {
+                    mLastTrack->meta.setInt32(kKeyBitsPerSample, sample_size);
+                    if (chunk_type == FOURCC('t', 'w', 'o', 's')) {
+                        mLastTrack->meta.setInt32(kKeyPcmBigEndian, 1);
+                    }
+                }
             }
             ALOGV("*** coding='%s' %d channels, size %d, rate %d\n",
                    chunk, num_channels, sample_size, sample_rate);
@@ -3947,6 +3962,7 @@
       mIsAVC(false),
       mIsHEVC(false),
       mIsAC4(false),
+      mIsPcm(false),
       mNALLengthSize(0),
       mStarted(false),
       mGroup(NULL),
@@ -4009,6 +4025,27 @@
         mNALLengthSize = 1 + (ptr[14 + 7] & 3);
     }
 
+    mIsPcm = !strcasecmp(mime, MEDIA_MIMETYPE_AUDIO_RAW);
+
+    if (mIsPcm) {
+        int32_t numChannels = 0;
+        int32_t bitsPerSample = 0;
+        CHECK(mFormat.findInt32(kKeyBitsPerSample, &bitsPerSample));
+        CHECK(mFormat.findInt32(kKeyChannelCount, &numChannels));
+
+        int32_t bytesPerSample = bitsPerSample >> 3;
+        int32_t pcmSampleSize = bytesPerSample * numChannels;
+
+        size_t maxSampleSize;
+        status_t err = mSampleTable->getMaxSampleSize(&maxSampleSize);
+        if (err != OK || maxSampleSize != static_cast<size_t>(pcmSampleSize) || bitsPerSample != 16) {
+            // Not supported
+            mIsPcm = false;
+        } else {
+            mFormat.setInt32(kKeyMaxInputSize, pcmSampleSize * kMaxPcmFrameSize);
+        }
+    }
+
     CHECK(format.findInt32(kKeyTrackID, &mTrackId));
 
 }
@@ -4923,34 +4960,78 @@
 
     if ((!mIsAVC && !mIsHEVC && !mIsAC4) || mWantsNALFragments) {
         if (newBuffer) {
-            ssize_t num_bytes_read =
-                mDataSource->readAt(offset, (uint8_t *)mBuffer->data(), size);
+            if (mIsPcm) {
+                // The twos' PCM block reader assumes that all samples has the same size.
 
-            if (num_bytes_read < (ssize_t)size) {
-                mBuffer->release();
-                mBuffer = NULL;
+                uint32_t samplesToRead = mSampleTable->getLastSampleIndexInChunk()
+                                                      - mCurrentSampleIndex + 1;
+                if (samplesToRead > kMaxPcmFrameSize) {
+                    samplesToRead = kMaxPcmFrameSize;
+                }
 
-                return ERROR_IO;
-            }
+                ALOGV("Reading %d PCM frames of size %zu at index %d to stop of chunk at %d",
+                      samplesToRead, size, mCurrentSampleIndex,
+                      mSampleTable->getLastSampleIndexInChunk());
 
-            CHECK(mBuffer != NULL);
-            mBuffer->set_range(0, size);
-            mBuffer->meta_data().clear();
-            mBuffer->meta_data().setInt64(
-                    kKeyTime, ((int64_t)cts * 1000000) / mTimescale);
-            mBuffer->meta_data().setInt64(
-                    kKeyDuration, ((int64_t)stts * 1000000) / mTimescale);
+               size_t totalSize = samplesToRead * size;
+                uint8_t* buf = (uint8_t *)mBuffer->data();
+                ssize_t bytesRead = mDataSource->readAt(offset, buf, totalSize);
+                if (bytesRead < (ssize_t)totalSize) {
+                    mBuffer->release();
+                    mBuffer = NULL;
 
-            if (targetSampleTimeUs >= 0) {
-                mBuffer->meta_data().setInt64(
-                        kKeyTargetTime, targetSampleTimeUs);
-            }
+                    return ERROR_IO;
+                }
 
-            if (isSyncSample) {
+                mBuffer->meta_data().clear();
+                mBuffer->meta_data().setInt64(kKeyTime, ((int64_t)cts * 1000000) / mTimescale);
                 mBuffer->meta_data().setInt32(kKeyIsSyncFrame, 1);
-            }
 
-            ++mCurrentSampleIndex;
+                int32_t byteOrder;
+                mFormat.findInt32(kKeyPcmBigEndian, &byteOrder);
+
+                if (byteOrder == 1) {
+                    // Big-endian -> little-endian
+                    uint16_t *dstData = (uint16_t *)buf;
+                    uint16_t *srcData = (uint16_t *)buf;
+
+                    for (size_t j = 0; j < bytesRead / sizeof(uint16_t); j++) {
+                         dstData[j] = ntohs(srcData[j]);
+                    }
+                }
+
+                mCurrentSampleIndex += samplesToRead;
+                mBuffer->set_range(0, totalSize);
+            } else {
+                ssize_t num_bytes_read =
+                    mDataSource->readAt(offset, (uint8_t *)mBuffer->data(), size);
+
+                if (num_bytes_read < (ssize_t)size) {
+                    mBuffer->release();
+                    mBuffer = NULL;
+
+                    return ERROR_IO;
+                }
+
+                CHECK(mBuffer != NULL);
+                mBuffer->set_range(0, size);
+                mBuffer->meta_data().clear();
+                mBuffer->meta_data().setInt64(
+                        kKeyTime, ((int64_t)cts * 1000000) / mTimescale);
+                mBuffer->meta_data().setInt64(
+                        kKeyDuration, ((int64_t)stts * 1000000) / mTimescale);
+
+                if (targetSampleTimeUs >= 0) {
+                    mBuffer->meta_data().setInt64(
+                            kKeyTargetTime, targetSampleTimeUs);
+                }
+
+                if (isSyncSample) {
+                    mBuffer->meta_data().setInt32(kKeyIsSyncFrame, 1);
+                }
+ 
+                ++mCurrentSampleIndex;
+            }
         }
 
         if (!mIsAVC && !mIsHEVC && !mIsAC4) {
diff --git a/media/extractors/mp4/SampleIterator.h b/media/extractors/mp4/SampleIterator.h
index 6a3fd3b..6e4f60e 100644
--- a/media/extractors/mp4/SampleIterator.h
+++ b/media/extractors/mp4/SampleIterator.h
@@ -36,6 +36,11 @@
     uint32_t getSampleTime() const { return mCurrentSampleTime; }
     uint32_t getSampleDuration() const { return mCurrentSampleDuration; }
 
+    uint32_t getLastSampleIndexInChunk() const {
+        return mCurrentSampleIndex + mSamplesPerChunk -
+                ((mCurrentSampleIndex - mFirstChunkSampleIndex) % mSamplesPerChunk) - 1;
+    }
+
     status_t getSampleSizeDirect(
             uint32_t sampleIndex, size_t *size);
 
diff --git a/media/extractors/mp4/SampleTable.cpp b/media/extractors/mp4/SampleTable.cpp
index 81c353e..28fe717 100644
--- a/media/extractors/mp4/SampleTable.cpp
+++ b/media/extractors/mp4/SampleTable.cpp
@@ -946,6 +946,11 @@
             sampleIndex, sampleSize);
 }
 
+uint32_t SampleTable::getLastSampleIndexInChunk() {
+    Mutex::Autolock autoLock(mLock);
+    return mSampleIterator->getLastSampleIndexInChunk();
+}
+
 status_t SampleTable::getMetaDataForSample(
         uint32_t sampleIndex,
         off64_t *offset,
diff --git a/media/extractors/mp4/SampleTable.h b/media/extractors/mp4/SampleTable.h
index e4e974b..dd68860 100644
--- a/media/extractors/mp4/SampleTable.h
+++ b/media/extractors/mp4/SampleTable.h
@@ -69,6 +69,9 @@
             bool *isSyncSample = NULL,
             uint32_t *sampleDuration = NULL);
 
+    // call only after getMetaDataForSample has been called successfully.
+    uint32_t getLastSampleIndexInChunk();
+
     enum {
         kFlagBefore,
         kFlagAfter,
diff --git a/media/libmediaextractor/include/media/stagefright/MetaDataBase.h b/media/libmediaextractor/include/media/stagefright/MetaDataBase.h
index dfe34e8..2e9aede 100644
--- a/media/libmediaextractor/include/media/stagefright/MetaDataBase.h
+++ b/media/libmediaextractor/include/media/stagefright/MetaDataBase.h
@@ -53,6 +53,7 @@
     kKeyFrameRate         = 'frmR',  // int32_t (video frame rate fps)
     kKeyBitRate           = 'brte',  // int32_t (bps)
     kKeyMaxBitRate        = 'mxBr',  // int32_t (bps)
+    kKeyBitsPerSample     = 'bits',  // int32_t (bits per sample)
     kKeyStreamHeader      = 'stHd',  // raw data
     kKeyESDS              = 'esds',  // raw data
     kKeyAACProfile        = 'aacp',  // int32_t
@@ -225,6 +226,7 @@
     kKeyExifOffset       = 'exof', // int64_t, Exif data offset
     kKeyExifSize         = 'exsz', // int64_t, Exif data size
     kKeyIsExif           = 'exif', // bool (int32_t) buffer contains exif data block
+    kKeyPcmBigEndian     = 'pcmb', // bool (int32_t)
 };
 
 enum {