diff --git a/trunk/src/app/srs_app_edge.cpp b/trunk/src/app/srs_app_edge.cpp
index 251e27f11..c347295d6 100644
--- a/trunk/src/app/srs_app_edge.cpp
+++ b/trunk/src/app/srs_app_edge.cpp
@@ -44,6 +44,7 @@ using namespace std;
 #include <srs_app_utility.hpp>
 #include <srs_protocol_amf0.hpp>
 #include <srs_kernel_utility.hpp>
+#include <srs_kernel_balance.hpp>
 
 // when error, edge ingester sleep for a while and retry.
 #define SRS_EDGE_INGESTER_SLEEP_US (int64_t)(1*1000*1000LL)
@@ -67,10 +68,9 @@ SrsEdgeIngester::SrsEdgeIngester()
     client = NULL;
     _edge = NULL;
     _req = NULL;
-    origin_index = 0;
     stream_id = 0;
     stfd = NULL;
-    curr_origin_server = "";
+    lb = new SrsLbRoundRobin();
     pthread = new SrsReusableThread2("edge-igs", this, SRS_EDGE_INGESTER_SLEEP_US);
 }
 
@@ -78,6 +78,7 @@ SrsEdgeIngester::~SrsEdgeIngester()
 {
     stop();
     
+    srs_freep(lb);
     srs_freep(pthread);
     srs_freep(kbps);
 }
@@ -121,7 +122,7 @@ void SrsEdgeIngester::stop()
 
 string SrsEdgeIngester::get_curr_origin()
 {
-    return curr_origin_server;
+    return lb->selected();
 }
 
 int SrsEdgeIngester::cycle()
@@ -130,7 +131,8 @@ int SrsEdgeIngester::cycle()
 
     _source->on_source_id_changed(_srs_context->get_id());
         
-    std::string ep_server, ep_port;
+    std::string ep_server;
+    int ep_port;
     if ((ret = connect_server(ep_server, ep_port)) != ERROR_SUCCESS) {
         return ret;
     }
@@ -216,7 +218,7 @@ int SrsEdgeIngester::ingest()
 }
 
 // TODO: FIXME: refine the connect_app.
-int SrsEdgeIngester::connect_app(string ep_server, string ep_port)
+int SrsEdgeIngester::connect_app(string ep_server, int ep_port)
 {
     int ret = ERROR_SUCCESS;
     
@@ -258,7 +260,7 @@ int SrsEdgeIngester::connect_app(string ep_server, string ep_port)
     // generate the tcUrl
     std::string param = "";
     std::string tc_url = srs_generate_tc_url(ep_server, vhost, req->app, ep_port, param);
-    srs_trace("edge ingest from %s:%s at %s", ep_server.c_str(), ep_port.c_str(), tc_url.c_str());
+    srs_trace("edge ingest from %s:%d at %s", ep_server.c_str(), ep_port, tc_url.c_str());
     
     // replace the tcUrl in request,
     // which will replace the tc_url in client.connect_app().
@@ -339,7 +341,7 @@ void SrsEdgeIngester::close_underlayer_socket()
     srs_close_stfd(stfd);
 }
 
-int SrsEdgeIngester::connect_server(string& ep_server, string& ep_port)
+int SrsEdgeIngester::connect_server(string& ep_server, int& ep_port)
 {
     int ret = ERROR_SUCCESS;
     
@@ -358,21 +360,13 @@ int SrsEdgeIngester::connect_server(string& ep_server, string& ep_port)
     }
     
     // select the origin.
-    std::string server = curr_origin_server = conf->args.at(origin_index % conf->args.size());
-    origin_index = (origin_index + 1) % conf->args.size();
-
-    std::string s_port = SRS_CONSTS_RTMP_DEFAULT_PORT;
+    std::string server = lb->select(conf->args);
     int port = ::atoi(SRS_CONSTS_RTMP_DEFAULT_PORT);
-    size_t pos = server.find(":");
-    if (pos != std::string::npos) {
-        s_port = server.substr(pos + 1);
-        server = server.substr(0, pos);
-        port = ::atoi(s_port.c_str());
-    }
+    srs_parse_hostport(server, server, port);
     
     // output the connected server and port.
     ep_server = server;
-    ep_port = s_port;
+    ep_port = port;
     
     // open socket.
     int64_t timeout = SRS_EDGE_INGESTER_TIMEOUT_US;
diff --git a/trunk/src/app/srs_app_edge.hpp b/trunk/src/app/srs_app_edge.hpp
index 8efb70999..a8b555eb7 100644
--- a/trunk/src/app/srs_app_edge.hpp
+++ b/trunk/src/app/srs_app_edge.hpp
@@ -46,6 +46,7 @@ class SrsCommonMessage;
 class SrsMessageQueue;
 class ISrsProtocolReaderWriter;
 class SrsKbps;
+class SrsLbRoundRobin;
 
 /**
 * the state of edge, auto machine
@@ -88,9 +89,7 @@ private:
     ISrsProtocolReaderWriter* io;
     SrsKbps* kbps;
     SrsRtmpClient* client;
-    int origin_index;
-    // current origin server of current source.
-    std::string curr_origin_server;
+    SrsLbRoundRobin* lb;
 public:
     SrsEdgeIngester();
     virtual ~SrsEdgeIngester();
@@ -105,8 +104,8 @@ public:
 private:
     virtual int ingest();
     virtual void close_underlayer_socket();
-    virtual int connect_server(std::string& ep_server, std::string& ep_port);
-    virtual int connect_app(std::string ep_server, std::string ep_port);
+    virtual int connect_server(std::string& ep_server, int& ep_port);
+    virtual int connect_app(std::string ep_server, int ep_port);
     virtual int process_publish_message(SrsCommonMessage* msg);
 };
 
diff --git a/trunk/src/app/srs_app_ffmpeg.cpp b/trunk/src/app/srs_app_ffmpeg.cpp
index ca1f8850a..e7843057d 100644
--- a/trunk/src/app/srs_app_ffmpeg.cpp
+++ b/trunk/src/app/srs_app_ffmpeg.cpp
@@ -43,6 +43,7 @@ using namespace std;
 #include <srs_app_utility.hpp>
 #include <srs_app_process.hpp>
 #include <srs_core_autofree.hpp>
+#include <srs_kernel_utility.hpp>
 
 #ifdef SRS_AUTO_FFMPEG_STUB
 
@@ -248,12 +249,6 @@ int SrsFFMPEG::start()
         return ret;
     }
     
-    // prepare exec params
-    // @remark we should never use stack variable, use heap to alloc to make lldb happy.
-    #define SRS_TMP_SIZE 512
-    char* tmp = new char[SRS_TMP_SIZE];
-    SrsAutoFree(char, tmp);
-    
     // the argv for process.
     params.clear();
     
@@ -300,33 +295,28 @@ int SrsFFMPEG::start()
     if (vcodec != SRS_RTMP_ENCODER_COPY && vcodec != SRS_RTMP_ENCODER_NO_VIDEO) {
         if (vbitrate > 0) {
             params.push_back("-b:v");
-            snprintf(tmp, SRS_TMP_SIZE, "%d", vbitrate * 1000);
-            params.push_back(tmp);
+            params.push_back(srs_int2str(vbitrate * 1000));
         }
         
         if (vfps > 0) {
             params.push_back("-r");
-            snprintf(tmp, SRS_TMP_SIZE, "%.2f", vfps);
-            params.push_back(tmp);
+            params.push_back(srs_float2str(vfps));
         }
         
         if (vwidth > 0 && vheight > 0) {
             params.push_back("-s");
-            snprintf(tmp, SRS_TMP_SIZE, "%dx%d", vwidth, vheight);
-            params.push_back(tmp);
+            params.push_back(srs_int2str(vwidth) + "x" + srs_int2str(vheight));
         }
         
         // TODO: add aspect if needed.
         if (vwidth > 0 && vheight > 0) {
             params.push_back("-aspect");
-            snprintf(tmp, SRS_TMP_SIZE, "%d:%d", vwidth, vheight);
-            params.push_back(tmp);
+            params.push_back(srs_int2str(vwidth) + ":" + srs_int2str(vheight));
         }
         
         if (vthreads > 0) {
             params.push_back("-threads");
-            snprintf(tmp, SRS_TMP_SIZE, "%d", vthreads);
-            params.push_back(tmp);
+            params.push_back(srs_int2str(vthreads));
         }
         
         params.push_back("-profile:v");
@@ -360,20 +350,17 @@ int SrsFFMPEG::start()
         if (acodec != SRS_RTMP_ENCODER_COPY) {
             if (abitrate > 0) {
                 params.push_back("-b:a");
-                snprintf(tmp, SRS_TMP_SIZE, "%d", abitrate * 1000);
-                params.push_back(tmp);
+                params.push_back(srs_int2str(abitrate * 1000));
             }
             
             if (asample_rate > 0) {
                 params.push_back("-ar");
-                snprintf(tmp, SRS_TMP_SIZE, "%d", asample_rate);
-                params.push_back(tmp);
+                params.push_back(srs_int2str(asample_rate));
             }
             
             if (achannels > 0) {
                 params.push_back("-ac");
-                snprintf(tmp, SRS_TMP_SIZE, "%d", achannels);
-                params.push_back(tmp);
+                params.push_back(srs_int2str(achannels));
             }
             
             // aparams
diff --git a/trunk/src/app/srs_app_kafka.cpp b/trunk/src/app/srs_app_kafka.cpp
index 175a50e3c..9eb821941 100644
--- a/trunk/src/app/srs_app_kafka.cpp
+++ b/trunk/src/app/srs_app_kafka.cpp
@@ -98,7 +98,7 @@ int SrsKafkaProducer::request_metadata()
     }
     
     srs_assert(!brokers->args.empty());
-    std::string broker = lb->select<string>(brokers->args);
+    std::string broker = lb->select(brokers->args);
     
     if (true) {
         std::string senabled = srs_bool2switch(enabled);
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
index c4af37664..89d568c20 100755
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -720,15 +720,12 @@ int SrsServer::acquire_pid_file()
         srs_error("truncate pid file %s error! ret=%#x", pid_file.c_str(), ret);
         return ret;
     }
-
-    int pid = (int)getpid();
     
     // write the pid
-    char buf[512];
-    snprintf(buf, sizeof(buf), "%d", pid);
-    if (write(fd, buf, strlen(buf)) != (int)strlen(buf)) {
+    string pid = srs_int2str(getpid());
+    if (write(fd, pid.c_str(), pid.length()) != pid.length()) {
         ret = ERROR_SYSTEM_PID_WRITE_FILE;
-        srs_error("write our pid error! pid=%d file=%s ret=%#x", pid, pid_file.c_str(), ret);
+        srs_error("write our pid error! pid=%s file=%s ret=%#x", pid.c_str(), pid_file.c_str(), ret);
         return ret;
     }
 
@@ -746,7 +743,7 @@ int SrsServer::acquire_pid_file()
         return ret;
     }
     
-    srs_trace("write pid=%d to %s success!", pid, pid_file.c_str());
+    srs_trace("write pid=%s to %s success!", pid.c_str(), pid_file.c_str());
     pid_fd = fd;
     
     return ret;
diff --git a/trunk/src/app/srs_app_utility.cpp b/trunk/src/app/srs_app_utility.cpp
index e06d83b30..7f25b82fe 100644
--- a/trunk/src/app/srs_app_utility.cpp
+++ b/trunk/src/app/srs_app_utility.cpp
@@ -204,8 +204,7 @@ string srs_path_build_timestamp(string template_path)
     // [timestamp],replace this const to current UNIX timestamp in ms.
     if (true) {
         int64_t now_us = ((int64_t)tv.tv_sec) * 1000 * 1000 + (int64_t)tv.tv_usec;
-        snprintf(buf, sizeof(buf), "%"PRId64, now_us / 1000);
-        path = srs_string_replace(path, "[timestamp]", buf);
+        path = srs_string_replace(path, "[timestamp]", srs_int2str(now_us / 1000));
     }
     
     return path;
diff --git a/trunk/src/kernel/srs_kernel_balance.cpp b/trunk/src/kernel/srs_kernel_balance.cpp
index b29ab3382..78f2808f4 100644
--- a/trunk/src/kernel/srs_kernel_balance.cpp
+++ b/trunk/src/kernel/srs_kernel_balance.cpp
@@ -23,6 +23,8 @@
 
 #include <srs_kernel_balance.hpp>
 
+using namespace std;
+
 SrsLbRoundRobin::SrsLbRoundRobin()
 {
     index = -1;
@@ -38,3 +40,18 @@ u_int32_t SrsLbRoundRobin::current()
     return index;
 }
 
+string SrsLbRoundRobin::selected()
+{
+    return elem;
+}
+
+string SrsLbRoundRobin::select(const vector<string>& servers)
+{
+    srs_assert(!servers.empty());
+    
+    index = (int)(count++ % servers.size());
+    elem = servers.at(index);
+    
+    return elem;
+}
+
diff --git a/trunk/src/kernel/srs_kernel_balance.hpp b/trunk/src/kernel/srs_kernel_balance.hpp
index 7bf3be5e3..057a6aec6 100644
--- a/trunk/src/kernel/srs_kernel_balance.hpp
+++ b/trunk/src/kernel/srs_kernel_balance.hpp
@@ -30,6 +30,7 @@
 #include <srs_core.hpp>
 
 #include <vector>
+#include <string>
 
 /**
  * the round-robin load balance algorithm,
@@ -42,21 +43,15 @@ private:
     int index;
     // total scheduled count.
     u_int32_t count;
+    // current selected server.
+    std::string elem;
 public:
     SrsLbRoundRobin();
     virtual ~SrsLbRoundRobin();
 public:
     virtual u_int32_t current();
-public:
-    template<typename T>
-    const T& select(const std::vector<T>& servers)
-    {
-        srs_assert(!servers.empty());
-        
-        index = (int)(count++ % servers.size());
-        
-        return servers.at(index);
-    }
+    virtual std::string selected();
+    virtual std::string select(const std::vector<std::string>& servers);
 };
 
 #endif
diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index ae93f7a84..3e06ac379 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -169,14 +169,43 @@ string srs_dns_resolve(string host)
     
     char ipv4[16];
     memset(ipv4, 0, sizeof(ipv4));
-    for (int i = 0; i < answer->h_length; i++) {
-        inet_ntop(AF_INET, answer->h_addr_list[i], ipv4, sizeof(ipv4));
-        break;
+    
+    // covert the first entry to ip.
+    if (answer->h_length > 0) {
+        inet_ntop(AF_INET, answer->h_addr_list[0], ipv4, sizeof(ipv4));
     }
     
     return ipv4;
 }
 
+void srs_parse_hostport(const string& hostport, string& host, int& port)
+{
+    host = hostport;
+    
+    size_t pos = hostport.find(":");
+    if (pos != std::string::npos) {
+        string p = hostport.substr(pos + 1);
+        host = hostport.substr(0, pos);
+        port = ::atoi(p.c_str());
+    }
+}
+
+string srs_int2str(int64_t value)
+{
+    // len(max int64_t) is 20, plus one "+-."
+    char tmp[22];
+    snprintf(tmp, 22, "%"PRId64, value);
+    return tmp;
+}
+
+string srs_float2str(double value)
+{
+    // len(max int64_t) is 20, plus one "+-."
+    char tmp[22];
+    snprintf(tmp, 22, "%.2f", value);
+    return tmp;
+}
+
 bool srs_is_little_endian()
 {
     // convert to network(big-endian) order, if not equals, 
diff --git a/trunk/src/kernel/srs_kernel_utility.hpp b/trunk/src/kernel/srs_kernel_utility.hpp
index 628833826..759bc383b 100644
--- a/trunk/src/kernel/srs_kernel_utility.hpp
+++ b/trunk/src/kernel/srs_kernel_utility.hpp
@@ -52,6 +52,13 @@ extern int64_t srs_update_system_time_ms();
 
 // dns resolve utility, return the resolved ip address.
 extern std::string srs_dns_resolve(std::string host);
+// split the host:port to host and port.
+extern void srs_parse_hostport(const std::string& hostport, std::string& host, int& port);
+
+// parse the int64 value to string.
+extern std::string srs_int2str(int64_t value);
+// parse the float value to string, precise is 2.
+extern std::string srs_float2str(double value);
 
 // whether system is little endian
 extern bool srs_is_little_endian();
diff --git a/trunk/src/protocol/srs_http_stack.cpp b/trunk/src/protocol/srs_http_stack.cpp
index 33f89e7af..e1fd3a310 100755
--- a/trunk/src/protocol/srs_http_stack.cpp
+++ b/trunk/src/protocol/srs_http_stack.cpp
@@ -174,9 +174,7 @@ int64_t SrsHttpHeader::content_length()
 
 void SrsHttpHeader::set_content_length(int64_t size)
 {
-    char buf[64];
-    snprintf(buf, sizeof(buf), "%"PRId64, size);
-    set("Content-Length", buf);
+    set("Content-Length", srs_int2str(size));
 }
 
 string SrsHttpHeader::content_type()
diff --git a/trunk/src/protocol/srs_protocol_json.cpp b/trunk/src/protocol/srs_protocol_json.cpp
index cf8369b71..60987626a 100644
--- a/trunk/src/protocol/srs_protocol_json.cpp
+++ b/trunk/src/protocol/srs_protocol_json.cpp
@@ -28,6 +28,7 @@ using namespace std;
 
 #include <srs_kernel_log.hpp>
 #include <srs_protocol_amf0.hpp>
+#include <srs_kernel_utility.hpp>
 
 /* json encode
  cout<< SRS_JOBJECT_START
@@ -328,10 +329,7 @@ string SrsJsonAny::dumps()
             return to_boolean()? "true":"false";
         }
         case SRS_JSON_Integer: {
-            // len(max int64_t) is 20, plus one "+-."
-            char tmp[22];
-            snprintf(tmp, 22, "%"PRId64, to_integer());
-            return tmp;
+            return srs_int2str(to_integer());
         }
         case SRS_JSON_Number: {
             // len(max int64_t) is 20, plus one "+-."
diff --git a/trunk/src/protocol/srs_protocol_utility.cpp b/trunk/src/protocol/srs_protocol_utility.cpp
index 9d9cd1999..60be8e561 100644
--- a/trunk/src/protocol/srs_protocol_utility.cpp
+++ b/trunk/src/protocol/srs_protocol_utility.cpp
@@ -125,6 +125,11 @@ void srs_random_generate(char* bytes, int size)
     }
 }
 
+string srs_generate_tc_url(string ip, string vhost, string app, int port, string param)
+{
+    return srs_generate_tc_url(ip, vhost, app, srs_int2str(port), param);
+}
+
 string srs_generate_tc_url(string ip, string vhost, string app, string port, string param)
 {
     string tcUrl = "rtmp://";
diff --git a/trunk/src/protocol/srs_protocol_utility.hpp b/trunk/src/protocol/srs_protocol_utility.hpp
index 05c2b7f27..beecf51a9 100644
--- a/trunk/src/protocol/srs_protocol_utility.hpp
+++ b/trunk/src/protocol/srs_protocol_utility.hpp
@@ -89,6 +89,10 @@ extern std::string srs_generate_tc_url(
     std::string ip, std::string vhost, std::string app, std::string port,
     std::string param
 );
+extern std::string srs_generate_tc_url(
+    std::string ip, std::string vhost, std::string app, int port,
+    std::string param
+);
 
 /**
 * compare the memory in bytes.