diff --git a/media/java/android/media/audiofx/Visualizer.java b/media/java/android/media/audiofx/Visualizer.java
index 3349277ede3b3..ea4027eab1589 100644
--- a/media/java/android/media/audiofx/Visualizer.java
+++ b/media/java/android/media/audiofx/Visualizer.java
@@ -110,10 +110,18 @@ public class Visualizer {
     public static final int MEASUREMENT_MODE_NONE = 0;
 
     /**
-     * Defines a measurement mode which computes the peak and RMS value in mB, where 0mB is the
-     * maximum sample value, and -9600mB is the minimum value.
-     * Values for peak and RMS can be retrieved with
-     * {@link #getMeasurementPeakRms(MeasurementPeakRms)}.
+     * Defines a measurement mode which computes the peak and RMS value in mB below the
+     * "full scale", where 0mB is normally the maximum sample value (but see the note
+     * below). Minimum value depends on the resolution of audio samples used by the audio
+     * framework. The value of -9600mB is the minimum value for 16-bit audio systems and
+     * -14400mB or below for "high resolution" systems. Values for peak and RMS can be
+     * retrieved with {@link #getMeasurementPeakRms(MeasurementPeakRms)}.
+     *
+     * <p class=note><strong>Note:</strong> when Visualizer effect is attached to the
+     * global session (with session ID 0), it is possible to observe RMS peaks higher than
+     * 0 dBFS, for example in the case when there are multiple audio sources playing
+     * simultaneously. In this case {@link #getMeasurementPeakRms(MeasurementPeakRms)}
+     * method can return a positive value.
      */
     public static final int MEASUREMENT_MODE_PEAK_RMS = 1 << 0;