diff --git a/include/media/nbaio/NBAIO.h b/include/media/nbaio/NBAIO.h
index 56896b9..be91c3a 100644
--- a/include/media/nbaio/NBAIO.h
+++ b/include/media/nbaio/NBAIO.h
@@ -126,7 +126,8 @@
 
 protected:
     NBAIO_Port(const NBAIO_Format& format) : mNegotiated(false), mFormat(format),
-                                             mBitShift(Format_frameBitShift(format)) { }
+                                             mBitShift(Format_frameBitShift(format)),
+                                             mFrameSize(Format_frameSize(format)) { }
     virtual ~NBAIO_Port() { }
 
     // Implementations are free to ignore these if they don't need them
@@ -134,6 +135,7 @@
     bool            mNegotiated;    // mNegotiated implies (mFormat != Format_Invalid)
     NBAIO_Format    mFormat;        // (mFormat != Format_Invalid) does not imply mNegotiated
     size_t          mBitShift;      // assign in parallel with any assignment to mFormat
+    size_t          mFrameSize;     // assign in parallel with any assignment to mFormat
 };
 
 // Abstract class (interface) representing a non-blocking data sink, for use by a data provider.
diff --git a/include/media/nbaio/SourceAudioBufferProvider.h b/include/media/nbaio/SourceAudioBufferProvider.h
index cdfb6fe..7357aa5 100644
--- a/include/media/nbaio/SourceAudioBufferProvider.h
+++ b/include/media/nbaio/SourceAudioBufferProvider.h
@@ -42,6 +42,7 @@
 private:
     const sp<NBAIO_Source> mSource;     // the wrapped source
     /*const*/ size_t    mFrameBitShift; // log2(frame size in bytes)
+    /*const*/ size_t    mFrameSize; // frame size in bytes
     void*               mAllocated; // pointer to base of allocated memory
     size_t              mSize;      // size of mAllocated in frames
     size_t              mOffset;    // frame offset within mAllocated of valid data