diff --git a/src/mp4util.cpp b/src/mp4util.cpp
index 47bd74e..932b22d 100644
--- a/src/mp4util.cpp
+++ b/src/mp4util.cpp
@@ -259,7 +259,8 @@
 
     // check if we can safely use integer operations
     if (ilog2(t) + ilog2(newTimeScale) <= 64) {
-        return (t * newTimeScale) / oldTimeScale;
+      // convert with rounding.
+      return (t * newTimeScale + oldTimeScale / 2) / oldTimeScale;
     }
 
     // final resort is to use floating point