diff --git a/util/mp4extract.cpp b/util/mp4extract.cpp
index 1e3c232..9bf7a0a 100644
--- a/util/mp4extract.cpp
+++ b/util/mp4extract.cpp
@@ -192,7 +192,7 @@
 
     if( !sampleMode ) {
         if( !dstFileName ) {
-            stringstream ss;
+            std::stringstream ss;
             ss << Mp4FileName << ".t" << trackId;
             outName = ss.str();
         } else {
@@ -226,7 +226,7 @@
         }
 
         if ( sampleMode ) {
-            stringstream ss;
+            std::stringstream ss;
             ss << Mp4FileName << ".t" << trackId << ".s" << sampleId;
             outName = ss.str();