diff --git a/include/hardware/camera3.h b/include/hardware/camera3.h
index a7df0ee..cce0deb 100644
--- a/include/hardware/camera3.h
+++ b/include/hardware/camera3.h
@@ -1479,6 +1479,13 @@
      *      android.lens.opticalStabilizationMode (if it is supported)
      *      android.scaler.cropRegion
      *      android.statistics.faceDetectMode (if it is supported)
+     *   6. To reduce the amount of data passed across process boundaries at
+     *      high frame rate, within one batch, camera framework only propagates
+     *      the last shutter notify and the last capture results (including partial
+     *      results and final result) to the app. The shutter notifies and capture
+     *      results for the other requests in the batch are derived by
+     *      the camera framework. As a result, the HAL can return empty metadata
+     *      except for the last result in the batch.
      *
      * For more details about high speed stream requirements, see
      * android.control.availableHighSpeedVideoConfigurations and CONSTRAINED_HIGH_SPEED_VIDEO