diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index f3b4bb33a..4d72336b6 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -4418,3 +4418,18 @@ bool srs_config_dvr_is_plan_append(string plan)
 {
     return plan == SRS_CONF_DEFAULT_DVR_PLAN_APPEND;
 }
+
+bool srs_stream_caster_is_udp(string caster)
+{
+    return caster == SRS_CONF_DEFAULT_STREAM_CASTER_MPEGTS_OVER_UDP;
+}
+
+bool srs_stream_caster_is_rtsp(string caster)
+{
+    return caster == SRS_CONF_DEFAULT_STREAM_CASTER_RTSP;
+}
+
+bool srs_stream_caster_is_flv(string caster)
+{
+    return caster == SRS_CONF_DEFAULT_STREAM_CASTER_FLV;
+}
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 8b7f5b854..2378d1e65 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -1143,6 +1143,9 @@ extern bool srs_config_ingest_is_stream(std::string type);
 extern bool srs_config_dvr_is_plan_segment(std::string plan);
 extern bool srs_config_dvr_is_plan_session(std::string plan);
 extern bool srs_config_dvr_is_plan_append(std::string plan);
+extern bool srs_stream_caster_is_udp(std::string caster);
+extern bool srs_stream_caster_is_rtsp(std::string caster);
+extern bool srs_stream_caster_is_flv(std::string caster);
 
 // global config
 extern SrsConfig* _srs_config;
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
index 0f2b3f960..3591c8289 100644
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -1120,11 +1120,11 @@ int SrsServer::listen_stream_caster()
         SrsListener* listener = NULL;
 
         std::string caster = _srs_config->get_stream_caster_engine(stream_caster);
-        if (caster == SRS_CONF_DEFAULT_STREAM_CASTER_MPEGTS_OVER_UDP) {
+        if (srs_stream_caster_is_udp(caster)) {
             listener = new SrsUdpCasterListener(this, SrsListenerMpegTsOverUdp, stream_caster);
-        } else if (caster == SRS_CONF_DEFAULT_STREAM_CASTER_RTSP) {
+        } else if (srs_stream_caster_is_rtsp(caster)) {
             listener = new SrsRtspListener(this, SrsListenerRtsp, stream_caster);
-        } else if (caster == SRS_CONF_DEFAULT_STREAM_CASTER_FLV) {
+        } else if (srs_stream_caster_is_flv(caster)) {
             listener = new SrsHttpFlvListener(this, SrsListenerFlv, stream_caster);
         } else {
             ret = ERROR_STREAM_CASTER_ENGINE;