diff --git a/lib/dtsc.cpp b/lib/dtsc.cpp
index c887cfed..9c8f2c88 100644
--- a/lib/dtsc.cpp
+++ b/lib/dtsc.cpp
@@ -356,6 +356,7 @@ void DTSC::Stream::addPacket(JSON::Value & newPack){
       if (metadata["tracks"][track]["frags"].size() > 0){
         // delete fragments of which the beginning can no longer be reached
         while (metadata["tracks"][track]["frags"].size() > 0 && metadata["tracks"][track]["frags"][0u]["num"].asInt() < metadata["tracks"][track]["keys"][0u]["num"].asInt()){
+          metadata["tracks"][track]["firstms"] = metadata["tracks"][track]["firstms"].asInt() + metadata["tracks"][track]["frags"][0u]["dur"].asInt();
           metadata["tracks"][track]["frags"].shrink(metadata["tracks"][track]["frags"].size() - 1);
           // increase the missed fragments counter
           metadata["tracks"][track]["missed_frags"] = metadata["tracks"][track]["missed_frags"].asInt() + 1;