diff --git a/trunk/src/app/srs_app_dash.hpp b/trunk/src/app/srs_app_dash.hpp
index 48dadd440..88f9c8489 100644
--- a/trunk/src/app/srs_app_dash.hpp
+++ b/trunk/src/app/srs_app_dash.hpp
@@ -129,7 +129,7 @@ private:
     uint64_t audio_dts;
     uint64_t video_dts;
 private:
-    // The fragment duration in ms to reap it.
+    // The fragment duration in srs_utime_t to reap it.
     srs_utime_t fragment;
 private:
     std::string home;
diff --git a/trunk/src/app/srs_app_fragment.cpp b/trunk/src/app/srs_app_fragment.cpp
index 661ac3444..efadb9022 100644
--- a/trunk/src/app/srs_app_fragment.cpp
+++ b/trunk/src/app/srs_app_fragment.cpp
@@ -53,12 +53,12 @@ void SrsFragment::append(int64_t dts)
     }
 
     if (start_dts == -1) {
-        start_dts = dts;
+        start_dts = dts * SRS_UTIME_MILLISECONDS;
     }
     
     // TODO: FIXME: Use cumulus dts.
-    start_dts = srs_min(start_dts, dts);
-    dur = srs_utime_t(dts - start_dts) * SRS_UTIME_MILLISECONDS;
+    start_dts = srs_min(start_dts, dts * SRS_UTIME_MILLISECONDS);
+    dur = dts - start_dts;
 }
 
 srs_utime_t SrsFragment::duration()
diff --git a/trunk/src/app/srs_app_fragment.hpp b/trunk/src/app/srs_app_fragment.hpp
index 0e70adf2e..c06add374 100644
--- a/trunk/src/app/srs_app_fragment.hpp
+++ b/trunk/src/app/srs_app_fragment.hpp
@@ -40,8 +40,8 @@ private:
     srs_utime_t dur;
     // The full file path of fragment.
     std::string filepath;
-    // The start DTS in ms of segment.
-    int64_t start_dts;
+    // The start DTS in srs_utime_t of segment.
+    srs_utime_t start_dts;
     // Whether current segement contains sequence header.
     bool sequence_header;
 public: