diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 3504f1f..b82f814 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -422,6 +422,7 @@
      * After error return:
      *  frameCount  0
      *  size        0
+     *  raw         undefined
      * After successful return:
      *  frameCount  actual number of frames available, <= number requested
      *  size        actual number of bytes available
@@ -510,7 +511,13 @@
     uint32_t                mFrameCount;
 
     audio_track_cblk_t*     mCblk;                  // re-load after mLock.unlock()
-    void*                   mBuffers;               // starting address of buffers in shared memory
+
+            // Starting address of buffers in shared memory.  If there is a shared buffer, mBuffers
+            // is the value of pointer() for the shared buffer, otherwise mBuffers points
+            // immediately after the control block.  This address is for the mapping within client
+            // address space.  AudioFlinger::TrackBase::mBuffer is for the server address space.
+    void*                   mBuffers;
+
     audio_format_t          mFormat;
     audio_stream_type_t     mStreamType;
     uint8_t                 mChannelCount;
diff --git a/include/private/media/AudioTrackShared.h b/include/private/media/AudioTrackShared.h
index 3063448..bbc5e26 100644
--- a/include/private/media/AudioTrackShared.h
+++ b/include/private/media/AudioTrackShared.h
@@ -54,9 +54,10 @@
                 uint32_t    serverBase;
 
                 int         mPad1;          // unused, but preserves cache line alignment
+
                 uint32_t    frameCount;
 
-                // Cache line boundary
+                // Cache line boundary (32 bytes)
 
                 uint32_t    loopStart;
                 uint32_t    loopEnd;        // read-only for server, read/write for client