diff --git a/lib/dtsc.h b/lib/dtsc.h
index 4326c588..7f617a22 100644
--- a/lib/dtsc.h
+++ b/lib/dtsc.h
@@ -275,6 +275,7 @@ namespace DTSC {
       unsigned int timeToFragnum(unsigned int timestamp);
       void reset();
       void toPrettyString(std::ostream & str, int indent = 0, int verbosity = 0);
+      void finalize();
       
       std::string getIdentifier();
       std::string getWritableIdentifier();
diff --git a/lib/dtscmeta.cpp b/lib/dtscmeta.cpp
index e1f62386..45c3815a 100644
--- a/lib/dtscmeta.cpp
+++ b/lib/dtscmeta.cpp
@@ -1114,6 +1114,10 @@ namespace DTSC {
     fragments.rbegin()->setSize(fragments.rbegin()->getSize() + packDataSize);
   }
   
+  void Track::finalize(){
+    keys.rbegin()->setLength(lastms - keys.rbegin()->getTime() + parts.rbegin()->getDuration());
+  }
+  
   ///\brief Returns a key given its number, or an empty key if the number is out of bounds
   Key & Track::getKey(unsigned int keyNum) {
     static Key empty;