--- a/dom/media/webaudio/AudioBlock.h
+++ b/dom/media/webaudio/AudioBlock.h
@@ -120,17 +120,17 @@ public:
 private:
   void ClearDownstreamMark();
   bool CanWrite();
 
   // mBufferIsDownstreamRef is set only when mBuffer references an
   // AudioBlockBuffer created in a different AudioBlock.  That can happen when
   // this AudioBlock is on a node downstream from the node which created the
   // buffer.  When this is set, the AudioBlockBuffer is notified that this
-  // reference does prevent the upstream node from re-using the buffer next
+  // reference does not prevent the upstream node from re-using the buffer next
   // iteration and modifying its contents.  The AudioBlockBuffer is also
   // notified when mBuffer releases this reference.
   bool mBufferIsDownstreamRef = false;
 };
 
 } // namespace mozilla
 
 #endif // MOZILLA_AUDIOBLOCK_H_