diff --git a/trunk/src/kernel/srs_kernel_flv.cpp b/trunk/src/kernel/srs_kernel_flv.cpp
index a06e387df..0706cd487 100644
--- a/trunk/src/kernel/srs_kernel_flv.cpp
+++ b/trunk/src/kernel/srs_kernel_flv.cpp
@@ -361,19 +361,26 @@ SrsSharedPtrMessage* SrsSharedPtrMessage::copy()
 {
     srs_assert(ptr);
     
+    SrsSharedPtrMessage* copy = copy2();
+    
+    copy->timestamp = timestamp;
+    copy->stream_id = stream_id;
+    copy->payload = ptr->payload;
+    copy->size = ptr->size;
+
+    return copy;
+}
+
+SrsSharedPtrMessage* SrsSharedPtrMessage::copy2()
+{
     SrsSharedPtrMessage* copy = _srs_rtp_msg_cache_objs->allocate();
 
     // We got an object from cache, the ptr might exists, so unwrap it.
-    copy->unwrap();
+    //srs_assert(!copy->ptr);
 
     // Reference to this message instead.
     copy->ptr = ptr;
     ptr->shared_count++;
-    
-    copy->timestamp = timestamp;
-    copy->stream_id = stream_id;
-    copy->payload = ptr->payload;
-    copy->size = ptr->size;
 
     return copy;
 }
diff --git a/trunk/src/kernel/srs_kernel_flv.hpp b/trunk/src/kernel/srs_kernel_flv.hpp
index c5e96394d..0cc6102ac 100644
--- a/trunk/src/kernel/srs_kernel_flv.hpp
+++ b/trunk/src/kernel/srs_kernel_flv.hpp
@@ -351,6 +351,8 @@ public:
     // copy current shared ptr message, use ref-count.
     // @remark, assert object is created.
     virtual SrsSharedPtrMessage* copy();
+    // Only copy the buffer, without header fields.
+    virtual SrsSharedPtrMessage* copy2();
 };
 
 // Transmux RTMP packets to FLV stream.
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
index eb770735c..36822a43f 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
@@ -910,6 +910,8 @@ void SrsRtpPacket2::recycle_shared_msg()
     }
 
     if (!shared_msg->payload || shared_msg->size != kRtpPacketSize || shared_msg->count() > 0) {
+        // Note that we must unwrap the shared message, because this object pool only cache the
+        // shared message itself without payload.
         shared_msg->unwrap();
         _srs_rtp_msg_cache_objs->recycle(shared_msg);
         goto cleanup;
@@ -1007,7 +1009,7 @@ SrsRtpPacket2* SrsRtpPacket2::copy()
     cp->payload_type_ = payload_type_;
 
     cp->nalu_type = nalu_type;
-    cp->shared_msg = shared_msg->copy();
+    cp->shared_msg = shared_msg->copy2();
     cp->frame_type = frame_type;
 
     // For performance issue, do not copy the unused field.
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
index 1c119e0bc..b7947fa8c 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
@@ -591,8 +591,10 @@ extern SrsRtpObjectCacheManager<SrsRtpPacket2>* _srs_rtp_cache;
 extern SrsRtpObjectCacheManager<SrsRtpRawPayload>* _srs_rtp_raw_cache;
 extern SrsRtpObjectCacheManager<SrsRtpFUAPayload2>* _srs_rtp_fua_cache;
 
-// For RTP packet shared messages cache.
+// For shared message cache, with payload.
 extern SrsRtpObjectCacheManager<SrsSharedPtrMessage>* _srs_rtp_msg_cache_buffers;
+// For shared message cache, without payload.
+// Note that user must unwrap the shared message, before recycle it.
 extern SrsRtpObjectCacheManager<SrsSharedPtrMessage>* _srs_rtp_msg_cache_objs;
 
 #endif