diff --git a/src/java/com/threerings/media/timer/CalibratingTimer.java b/src/java/com/threerings/media/timer/CalibratingTimer.java
new file mode 100644
index 00000000..6b146927
--- /dev/null
+++ b/src/java/com/threerings/media/timer/CalibratingTimer.java
@@ -0,0 +1,103 @@
+package com.threerings.media.timer;
+
+import com.samskivert.Log;
+
+/**
+ * Calibrates timing values from a subclass' implementation of current against those returned by
+ * System.currentTimeMillis. If the subclass timer is moving 1.25 times faster or .75 times slower
+ * than currentTimeMillis, hold it to the values from currentTimeMillis.
+ */
+public abstract class CalibratingTimer
+    implements MediaTimer
+{
+    /**
+     * Initializes this timer. Must be called before the timer is used.
+     * 
+     * @param milliDivider - value by which current() must be divided to get milliseconds
+     * @param microDivider - value by which current() must be divided to get microseconds
+     */
+    protected void init (long milliDivider, long microDivider)
+    {
+        _milliDivider = milliDivider;
+        _microDivider = microDivider;
+        reset();
+        Log.info("Using " + getClass() + " timer [mfreq=" + _milliDivider + ", ufreq="
+            + _microDivider + ", start=" + _startStamp + "].");
+    }
+
+    // documentation inherited from interface
+    public long getElapsedMicros ()
+    {
+        return elapsed() / _microDivider;
+    }
+
+    // documentation inherited from interface
+    public long getElapsedMillis ()
+    {
+        return elapsed() / _milliDivider;
+    }
+
+    // documentation inherited from interface
+    public void reset ()
+    {
+        _startStamp = current();
+        _driftMilliStamp = System.currentTimeMillis();
+        _driftTimerStamp = current();
+        _callsSinceCalibration = 0;
+    }
+
+    /** Returns the difference between _startStamp and current() */
+    protected long elapsed ()
+    {
+        if (_callsSinceCalibration++ > 1000) {
+            calibrate();
+        }
+        return (long)(((current() - _startStamp)) / _driftFactor);
+    }
+
+    /** Calculates the drift factor from the time elapsed from the last calibrate call. */
+    protected void calibrate ()
+    {
+        long elapsedNanos = (current() - _driftTimerStamp);
+        double elapsedMillis = System.currentTimeMillis() - _driftMilliStamp;
+        double drift = (elapsedNanos / 1000000L) / elapsedMillis;
+        if (drift > 1.25 || drift < 0.75) {
+            if (_driftFactor == 1.0) {
+                Log.warning("Calibrating [drift=" + drift + "]");
+            }
+            _driftFactor = drift;
+        } else if (_driftFactor != 1.0) {
+            // If we're within bounds now but we weren't before, reset _driftFactor and log it
+            _driftFactor = 1.0;
+            Log.warning("Calibrating [drift=" + drift + "]");
+        }
+        _driftMilliStamp = System.currentTimeMillis();
+        _driftTimerStamp = current();
+        _callsSinceCalibration = 0;
+    }
+
+    /** Return the current value for this timer. */
+    public abstract long current ();
+
+    /** current() value when the timer was started. */
+    protected long _startStamp;
+
+    /** Amount by which current() should be divided to get milliseconds. */
+    protected long _milliDivider;
+
+    /** Amount by which current() should be divided to get microseconds. */
+    protected long _microDivider;
+
+    /** currentTimeMillis() value from the last time we called calibrate. */
+    protected long _driftMilliStamp = System.currentTimeMillis();
+
+    /** current() value from the last time we called calibrate. */
+    protected long _driftTimerStamp;
+
+    /** Factor by which the timer values are drifting from currentTimeMillis. */
+    protected double _driftFactor = 1.0;
+
+    /** Number of calls to elapsed since we've called calibrate. */
+    protected int _callsSinceCalibration = 0;
+
+}
diff --git a/src/java/com/threerings/media/timer/NanoTimer.java b/src/java/com/threerings/media/timer/NanoTimer.java
index dd35091a..c0669e3b 100644
--- a/src/java/com/threerings/media/timer/NanoTimer.java
+++ b/src/java/com/threerings/media/timer/NanoTimer.java
@@ -25,26 +25,16 @@ package com.threerings.media.timer;
  * Uses the {@link System#nanoTime} method introduced in 1.5 to try to obtain higher resolution
  * timestamps than those available via {@link System#currentTimeMillis}.
  */
-public class NanoTimer implements MediaTimer
+public class NanoTimer extends CalibratingTimer
 {
-    // documentation inherited from interface
-    public void reset ()
+    public NanoTimer ()
     {
-        _resetStamp = System.nanoTime();
+        init(1000000, 1000);
     }
 
-    // documentation inherited from interface
-    public long getElapsedMillis ()
+    @Override
+    public long current ()
     {
-        return (System.nanoTime() - _resetStamp) / 1000000L;
+        return System.nanoTime();
     }
-
-    // documentation inherited from interface
-    public long getElapsedMicros ()
-    {
-        return (System.nanoTime() - _resetStamp) / 1000L;
-    }
-
-    /** The time at which this timer was last reset. */
-    protected long _resetStamp = System.nanoTime();
 }
diff --git a/src/java/com/threerings/media/timer/PerfTimer.java b/src/java/com/threerings/media/timer/PerfTimer.java
index 17a99112..408b3ff2 100644
--- a/src/java/com/threerings/media/timer/PerfTimer.java
+++ b/src/java/com/threerings/media/timer/PerfTimer.java
@@ -23,47 +23,23 @@ package com.threerings.media.timer;
 
 import sun.misc.Perf;
 
-import com.threerings.media.Log;
-
 /**
  * A timer that uses the performance clock exposed by Sun in JDK 1.4.2.
  */
-public class PerfTimer implements MediaTimer
+public class PerfTimer extends CalibratingTimer
 {
     public PerfTimer ()
     {
         _timer = Perf.getPerf();
-        _mfrequency = _timer.highResFrequency() / 1000;
-        _ufrequency = _timer.highResFrequency() / 1000000;
-        _startStamp = _timer.highResCounter();
-        Log.info("Using high performance timer [mfreq=" + _mfrequency +
-                 ", ufreq=" + _ufrequency + ", start=" + _startStamp + "].");
+        init(_timer.highResFrequency() / 1000, _timer.highResFrequency() / 1000000);
     }
 
-    // documentation inherited from interface
-    public void reset ()
+    @Override
+    public long current ()
     {
-        _startStamp = _timer.highResCounter();
-    }
-
-    // documentation inherited from interface
-    public long getElapsedMillis ()
-    {
-        return (_timer.highResCounter() - _startStamp) / _mfrequency;
-    }
-
-    // documentation inherited from interface
-    public long getElapsedMicros ()
-    {
-        return (_timer.highResCounter() - _startStamp) / _ufrequency;
+        return _timer.highResCounter();
     }
 
     /** A performance timer object. */
     protected Perf _timer;
-
-    /** The time at which this timer was last reset. */
-    protected long _startStamp;
-
-    /** The timer frequencies. */
-    protected long _mfrequency, _ufrequency;
 }