diff --git a/src/AudioIO.cpp b/src/AudioIO.cpp
index 6ce02ca2d..76542bdb6 100644
--- a/src/AudioIO.cpp
+++ b/src/AudioIO.cpp
@@ -4224,8 +4224,8 @@ int audacityAudioCallback(const void *inputBuffer, void *outputBuffer,
                                                          (int)framesPerBuffer);
                chanCnt++;
             }
-            // There should not be a difference of len in different loop passes...
-            // but anyway take a max.
+            // There can be a difference of len in different loop passes if one channel
+            // of a stereo track ends before the other!  Take a max!
             maxLen = std::max(maxLen, len);
 
 
@@ -4257,6 +4257,9 @@ int audacityAudioCallback(const void *inputBuffer, void *outputBuffer,
             }
 #endif
 
+            // Last channel seen now
+            len = maxLen;
+
             if( !cut && selected )
             {
                len = em.RealtimeProcess(group, chanCnt, tempBufs, len);