diff --git a/trunk/research/librtmp/srs_flv_injecter.c b/trunk/research/librtmp/srs_flv_injecter.c
index c9912ed06..5b6d866c3 100644
--- a/trunk/research/librtmp/srs_flv_injecter.c
+++ b/trunk/research/librtmp/srs_flv_injecter.c
@@ -26,6 +26,7 @@ gcc srs_flv_injecter.c ../../objs/lib/srs_librtmp.a -g -O0 -lstdc++ -o srs_flv_i
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include <sys/types.h>
diff --git a/trunk/research/librtmp/srs_play.c b/trunk/research/librtmp/srs_play.c
index e0710a433..960523a3b 100644
--- a/trunk/research/librtmp/srs_play.c
+++ b/trunk/research/librtmp/srs_play.c
@@ -52,34 +52,35 @@ int main(int argc, char** argv)
     
     rtmp = srs_rtmp_create(argv[1]);
     
-    printf("suck rtmp stream like rtmpdump\n");
-    printf("srs(simple-rtmp-server) client librtmp library.\n");
-    printf("version: %d.%d.%d\n", srs_version_major(), srs_version_minor(), srs_version_revision());
-    printf("rtmp url: %s\n", argv[1]);
+    srs_trace("suck rtmp stream like rtmpdump");
+    srs_trace("srs(simple-rtmp-server) client librtmp library.");
+    srs_trace("version: %d.%d.%d", srs_version_major(), srs_version_minor(), srs_version_revision());
+    srs_trace("rtmp url: %s", argv[1]);
     
     if (srs_simple_handshake(rtmp) != 0) {
-        printf("simple handshake failed.\n");
+        srs_trace("simple handshake failed.");
         goto rtmp_destroy;
     }
-    printf("simple handshake success\n");
+    srs_trace("simple handshake success");
     
     if (srs_connect_app(rtmp) != 0) {
-        printf("connect vhost/app failed.\n");
+        srs_trace("connect vhost/app failed.");
         goto rtmp_destroy;
     }
-    printf("connect vhost/app success\n");
+    srs_trace("connect vhost/app success");
     
     if (srs_play_stream(rtmp) != 0) {
-        printf("play stream failed.\n");
+        srs_trace("play stream failed.");
         goto rtmp_destroy;
     }
-    printf("play stream success\n");
+    srs_trace("play stream success");
     
     for (;;) {
         if (srs_read_packet(rtmp, &type, &timestamp, &data, &size) != 0) {
             goto rtmp_destroy;
         }
-        printf("got packet: type=%s, time=%d, size=%d\n", srs_type2string(type), timestamp, size);
+        srs_trace("got packet: type=%s, time=%d, size=%d", 
+            srs_type2string(type), timestamp, size);
         
         free(data);
     }
diff --git a/trunk/src/libs/srs_librtmp.cpp b/trunk/src/libs/srs_librtmp.cpp
index f0f4da313..6b59bacf0 100644
--- a/trunk/src/libs/srs_librtmp.cpp
+++ b/trunk/src/libs/srs_librtmp.cpp
@@ -30,6 +30,10 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <sstream>
 using namespace std;
 
+// undefine the log of librtmp for the srs use its log.
+#undef srs_trace
+#undef srs_verbose
+
 #include <srs_kernel_error.hpp>
 #include <srs_protocol_rtmp.hpp>
 #include <srs_lib_simple_socket.hpp>
diff --git a/trunk/src/libs/srs_librtmp.hpp b/trunk/src/libs/srs_librtmp.hpp
index e4f4669b6..66b1e9087 100644
--- a/trunk/src/libs/srs_librtmp.hpp
+++ b/trunk/src/libs/srs_librtmp.hpp
@@ -234,14 +234,11 @@ extern int srs_version_revision();
 extern int64_t srs_get_time_ms();
 extern int64_t srs_get_nsend_bytes(srs_rtmp_t rtmp);
 extern int64_t srs_get_nrecv_bytes(srs_rtmp_t rtmp);
-// log to console.
+
+// log to console, for use srs-librtmp application.
 extern const char* srs_format_time();
-#ifndef srs_trace
-    #define srs_trace(msg, ...) printf("[%s]", srs_format_time());printf(msg, ##__VA_ARGS__);printf("\n")
-#endif
-#ifndef srs_verbose
-    #define srs_verbose(msg, ...) printf("[%s]", srs_format_time());printf(msg, ##__VA_ARGS__);printf("\n")
-#endif
+#define srs_trace(msg, ...) printf("[%s]", srs_format_time());printf(msg, ##__VA_ARGS__);printf("\n")
+#define srs_verbose(msg, ...) printf("[%s]", srs_format_time());printf(msg, ##__VA_ARGS__);printf("\n")
 
 /*************************************************************
 **************************************************************