diff --git a/trunk/configure b/trunk/configure
index a072789b6..8a963b9bf 100755
--- a/trunk/configure
+++ b/trunk/configure
@@ -203,7 +203,7 @@ if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
     MODULE_ID="SERVICE"
     MODULE_DEPENDS=("CORE" "KERNEL" "PROTOCOL")
     ModuleLibIncs=(${LibSTRoot} ${SRS_OBJS_DIR} ${LibSSLRoot})
-    MODULE_FILES=("srs_service_log" "srs_service_st" "srs_service_http_client"
+    MODULE_FILES=("srs_service_log" "srs_service_time" "srs_service_st" "srs_service_http_client"
         "srs_service_http_conn" "srs_service_rtmp_conn" "srs_service_utility"
         "srs_service_conn")
     DEFINES=""
diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index b1ba652bf..c79cd4f48 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -5895,9 +5895,9 @@ bool SrsConfig::get_dash_enabled(string vhost)
     return SRS_CONF_PERFER_FALSE(conf->arg0());
 }
 
-int SrsConfig::get_dash_fragment(string vhost)
+srs_utime_t SrsConfig::get_dash_fragment(string vhost)
 {
-    static int DEFAULT = 3 * 1000;
+    static int DEFAULT = 3 * SRS_UTIME_SECONDS;
     
     SrsConfDirective* conf = get_dash(vhost);
     if (!conf) {
@@ -5909,7 +5909,7 @@ int SrsConfig::get_dash_fragment(string vhost)
         return DEFAULT;
     }
     
-    return (int)(1000 * ::atof(conf->arg0().c_str()));
+    return (srs_utime_t)(::atof(conf->arg0().c_str()) * SRS_UTIME_SECONDS);
 }
 
 int SrsConfig::get_dash_update_period(string vhost)
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 8fa591ace..266fdf476 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -34,7 +34,7 @@
 #include <srs_app_reload.hpp>
 #include <srs_app_async_call.hpp>
 #include <srs_app_thread.hpp>
-#include <srs_service_st.hpp>
+#include <srs_service_time.hpp>
 
 class SrsRequest;
 class SrsFileWriter;
@@ -1152,7 +1152,7 @@ public:
     // Whether DASH is enabled.
     virtual bool get_dash_enabled(std::string vhost);
     // Get the duration of segment in milliseconds.
-    virtual int get_dash_fragment(std::string vhost);
+    virtual srs_utime_t get_dash_fragment(std::string vhost);
     // Get the period to update MPD in milliseconds.
     virtual int get_dash_update_period(std::string vhost);
     // Get the depth of timeshift buffer in milliseconds.
diff --git a/trunk/src/app/srs_app_dash.cpp b/trunk/src/app/srs_app_dash.cpp
index 7061cfb99..3956cb73b 100644
--- a/trunk/src/app/srs_app_dash.cpp
+++ b/trunk/src/app/srs_app_dash.cpp
@@ -212,12 +212,12 @@ srs_error_t SrsMpdWriter::write(SrsFormat* format)
     << "    xmlns=\"urn:mpeg:dash:schema:mpd:2011\" xmlns:ns1=\"http://www.w3.org/2001/XMLSchema-instance\" " << endl
     << "    type=\"dynamic\" minimumUpdatePeriod=\"PT" << update_period / 1000 << "S\" " << endl
     << "    timeShiftBufferDepth=\"PT" << timeshit / 1000 << "S\" availabilityStartTime=\"1970-01-01T00:00:00Z\" " << endl
-    << "    maxSegmentDuration=\"PT" << fragment / 1000 << "S\" minBufferTime=\"PT" << fragment / 1000 << "S\" >" << endl
+    << "    maxSegmentDuration=\"PT" << fragment / SRS_UTIME_SECONDS << "S\" minBufferTime=\"PT" << fragment / SRS_UTIME_SECONDS << "S\" >" << endl
     << "    <BaseURL>" << req->stream << "/" << "</BaseURL>" << endl
     << "    <Period start=\"PT0S\">" << endl;
     if (format->acodec) {
         ss  << "        <AdaptationSet mimeType=\"audio/mp4\" segmentAlignment=\"true\" startWithSAP=\"1\">" << endl;
-        ss  << "            <SegmentTemplate duration=\"" << fragment / 1000 << "\" "
+        ss  << "            <SegmentTemplate duration=\"" << fragment / SRS_UTIME_SECONDS << "\" "
         << "initialization=\"$RepresentationID$-init.mp4\" "
         << "media=\"$RepresentationID$-$Number$.m4s\" />" << endl;
         ss  << "            <Representation id=\"audio\" bandwidth=\"48000\" codecs=\"mp4a.40.2\" />" << endl;
@@ -227,7 +227,7 @@ srs_error_t SrsMpdWriter::write(SrsFormat* format)
         int w = format->vcodec->width;
         int h = format->vcodec->height;
         ss  << "        <AdaptationSet mimeType=\"video/mp4\" segmentAlignment=\"true\" startWithSAP=\"1\">" << endl;
-        ss  << "            <SegmentTemplate duration=\"" << fragment / 1000 << "\" "
+        ss  << "            <SegmentTemplate duration=\"" << fragment / SRS_UTIME_SECONDS << "\" "
         << "initialization=\"$RepresentationID$-init.mp4\" "
         << "media=\"$RepresentationID$-$Number$.m4s\" />" << endl;
         ss  << "            <Representation id=\"video\" bandwidth=\"800000\" codecs=\"avc1.64001e\" "
@@ -265,8 +265,8 @@ srs_error_t SrsMpdWriter::get_fragment(bool video, std::string& home, std::strin
     
     home = fragment_home;
     
-    sn = srs_update_system_time_ms() / fragment;
-    basetime = sn * fragment;
+    sn = srs_update_system_time_ms() * SRS_UTIME_MILLISECONDS / fragment;
+    basetime = sn * fragment / SRS_UTIME_MILLISECONDS;
     
     if (video) {
         file_name = "video-" + srs_int2str(sn) + ".m4s";
@@ -335,7 +335,7 @@ srs_error_t SrsDashController::on_audio(SrsSharedPtrMessage* shared_audio, SrsFo
         return refresh_init_mp4(shared_audio, format);
     }
     
-    if (acurrent->duration() >= fragment) {
+    if (acurrent->duration() >= fragment / SRS_UTIME_MILLISECONDS) {
         if ((err = acurrent->reap(audio_dts)) != srs_success) {
             return srs_error_wrap(err, "reap current");
         }
@@ -367,7 +367,7 @@ srs_error_t SrsDashController::on_video(SrsSharedPtrMessage* shared_video, SrsFo
         return refresh_init_mp4(shared_video, format);
     }
     
-    bool reopen = format->video->frame_type == SrsVideoAvcFrameTypeKeyFrame && vcurrent->duration() >= fragment;
+    bool reopen = format->video->frame_type == SrsVideoAvcFrameTypeKeyFrame && vcurrent->duration() >= fragment / SRS_UTIME_MILLISECONDS;
     if (reopen) {
         if ((err = vcurrent->reap(video_dts)) != srs_success) {
             return srs_error_wrap(err, "reap current");
diff --git a/trunk/src/app/srs_app_dash.hpp b/trunk/src/app/srs_app_dash.hpp
index ea675ffca..5073a683b 100644
--- a/trunk/src/app/srs_app_dash.hpp
+++ b/trunk/src/app/srs_app_dash.hpp
@@ -30,6 +30,7 @@
 #include <vector>
 
 #include <srs_app_fragment.hpp>
+#include <srs_service_time.hpp>
 
 class SrsRequest;
 class SrsOriginHub;
@@ -86,7 +87,7 @@ private:
     int64_t last_update_mpd;
 private:
     // The duration of fragment in ms.
-    int fragment;
+    srs_utime_t fragment;
     // The period to update the mpd in ms.
     int update_period;
     // The timeshift buffer depth.
@@ -128,7 +129,7 @@ private:
     uint64_t video_dts;
 private:
     // The fragment duration in ms to reap it.
-    int fragment;
+    srs_utime_t fragment;
 private:
     std::string home;
     int video_tack_id;
diff --git a/trunk/src/app/srs_app_fragment.hpp b/trunk/src/app/srs_app_fragment.hpp
index 2bd5843aa..2495e9fc1 100644
--- a/trunk/src/app/srs_app_fragment.hpp
+++ b/trunk/src/app/srs_app_fragment.hpp
@@ -52,6 +52,7 @@ public:
     // @dts The dts of frame in ms.
     virtual void append(int64_t dts);
     // Get the duration of fragment in ms.
+    // TODO: FIXME: Refine to time unit.
     virtual int64_t duration();
     // Whether the fragment contains any sequence header.
     virtual bool is_sequence_header();
diff --git a/trunk/src/service/srs_service_st.hpp b/trunk/src/service/srs_service_st.hpp
index 4a6998517..c1f2bfcc7 100644
--- a/trunk/src/service/srs_service_st.hpp
+++ b/trunk/src/service/srs_service_st.hpp
@@ -29,6 +29,7 @@
 #include <string>
 
 #include <srs_protocol_io.hpp>
+#include <srs_service_time.hpp>
 
 // Wrap for coroutine.
 typedef void* srs_netfd_t;
diff --git a/trunk/src/service/srs_service_time.cpp b/trunk/src/service/srs_service_time.cpp
new file mode 100644
index 000000000..4cbaa8ead
--- /dev/null
+++ b/trunk/src/service/srs_service_time.cpp
@@ -0,0 +1,25 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2019 Winlin
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <srs_service_time.hpp>
+
diff --git a/trunk/src/service/srs_service_time.hpp b/trunk/src/service/srs_service_time.hpp
new file mode 100644
index 000000000..481fbc44b
--- /dev/null
+++ b/trunk/src/service/srs_service_time.hpp
@@ -0,0 +1,48 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2019 Winlin
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef SRS_SERVICE_TIME_HPP
+#define SRS_SERVICE_TIME_HPP
+
+#include <srs_core.hpp>
+
+// Wrap for coroutine.
+typedef uint64_t srs_utime_t;
+
+// The time unit in ms, for example 100 * SRS_UTIME_MILLISECONDS means 100ms.
+#define SRS_UTIME_MILLISECONDS 1000
+
+// The time unit in ms, for example 120 * SRS_UTIME_SECONDS means 120s.
+#define SRS_UTIME_SECONDS 1000000
+
+// The time unit in minutes, for example 3 * SRS_UTIME_MINUTES means 3m.
+#define SRS_UTIME_MINUTES 60000000LL
+
+// The time unit in hours, for example 2 * SRS_UTIME_HOURS means 2h.
+#define SRS_UTIME_HOURS 3600000000LL
+
+// Never timeout.
+#define SRS_UTIME_NO_TIMEOUT ((srs_utime_t) -1LL)
+
+#endif
+
diff --git a/trunk/src/utest/srs_utest_config.cpp b/trunk/src/utest/srs_utest_config.cpp
index 7e44c238d..be3f47c9c 100644
--- a/trunk/src/utest/srs_utest_config.cpp
+++ b/trunk/src/utest/srs_utest_config.cpp
@@ -1811,14 +1811,16 @@ VOID TEST(ConfigUnitTest, CheckDefaultValues)
 	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF));
 	    EXPECT_EQ(30 * SRS_UTIME_SECONDS, conf.get_bw_check_interval(""));
 
-	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF"vhost v{}"));
-	    EXPECT_EQ(30 * SRS_UTIME_SECONDS, conf.get_bw_check_interval("v"));
+	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF"vhost v{bandcheck{interval 4;}}"));
+	    EXPECT_EQ(4 * SRS_UTIME_SECONDS, conf.get_bw_check_interval("v"));
+    }
 
-	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF"vhost v{bandcheck{}}"));
-	    EXPECT_EQ(30 * SRS_UTIME_SECONDS, conf.get_bw_check_interval("v"));
+    if (true) {
+	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF));
+	    EXPECT_EQ(3 * SRS_UTIME_SECONDS, conf.get_dash_fragment(""));
 
-	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF"vhost v{bandcheck{interval 1.1;}}"));
-	    EXPECT_EQ(srs_utime_t(1.1 * SRS_UTIME_SECONDS), conf.get_bw_check_interval("v"));
+	    EXPECT_TRUE(ERROR_SUCCESS == conf.parse(_MIN_OK_CONF"vhost v{dash{dash_fragment 4;}}"));
+	    EXPECT_EQ(4 * SRS_UTIME_SECONDS, conf.get_dash_fragment("v"));
     }
 }