diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index fc24bed..38744d0 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -472,6 +472,10 @@
             const uint32_t      mSampleRate;    // initial sample rate only; for tracks which
                                 // support dynamic rates, the current value is in control block
             const audio_format_t mFormat;
+            size_t              mFrameSize; // AudioFlinger's view of frame size in shared memory,
+                                            // where for AudioTrack (but not AudioRecord),
+                                            // 8-bit PCM samples are stored as 16-bit
+                                            // FIXME should be const
             bool                mStepServerFailed;
             const int           mSessionId;
             uint8_t             mChannelCount;