diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 0b7b51846..d1744e4f2 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR "0"
 #define VERSION_MINOR "9"
-#define VERSION_REVISION "153"
+#define VERSION_REVISION "154"
 #define RTMP_SIG_SRS_VERSION VERSION_MAJOR"."VERSION_MINOR"."VERSION_REVISION
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
diff --git a/trunk/src/rtmp/srs_protocol_rtmp_stack.cpp b/trunk/src/rtmp/srs_protocol_rtmp_stack.cpp
index 2dbc6249e..253d090dd 100644
--- a/trunk/src/rtmp/srs_protocol_rtmp_stack.cpp
+++ b/trunk/src/rtmp/srs_protocol_rtmp_stack.cpp
@@ -297,8 +297,7 @@ SrsProtocol::AckWindowSize::AckWindowSize()
 
 SrsProtocol::SrsProtocol(ISrsProtocolReaderWriter* io)
 {
-    buffer = new SrsBuffer();
-    decode_stream = new SrsStream();
+    in_buffer = new SrsBuffer();
     skt = io;
     
     in_chunk_size = out_chunk_size = RTMP_DEFAULT_CHUNK_SIZE;
@@ -317,8 +316,7 @@ SrsProtocol::~SrsProtocol()
         chunk_streams.clear();
     }
     
-    srs_freep(decode_stream);
-    srs_freep(buffer);
+    srs_freep(in_buffer);
 }
 
 void SrsProtocol::set_recv_timeout(int64_t timeout_us)
@@ -406,10 +404,12 @@ int SrsProtocol::decode_message(SrsMessage* msg, SrsPacket** ppacket)
     srs_assert(msg != NULL);
     srs_assert(msg->payload != NULL);
     srs_assert(msg->size > 0);
+    
+    SrsStream stream;
 
     // initialize the decode stream for all message,
     // it's ok for the initialize if fast and without memory copy.
-    if ((ret = decode_stream->initialize((char*)(msg->payload), msg->size)) != ERROR_SUCCESS) {
+    if ((ret = stream.initialize((char*)(msg->payload), msg->size)) != ERROR_SUCCESS) {
         srs_error("initialize stream failed. ret=%d", ret);
         return ret;
     }
@@ -417,7 +417,7 @@ int SrsProtocol::decode_message(SrsMessage* msg, SrsPacket** ppacket)
     
     // decode the packet.
     SrsPacket* packet = NULL;
-    if ((ret = do_decode_message(msg->header, decode_stream, &packet)) != ERROR_SUCCESS) {
+    if ((ret = do_decode_message(msg->header, &stream, &packet)) != ERROR_SUCCESS) {
         srs_freep(packet);
         return ret;
     }
@@ -445,6 +445,8 @@ int SrsProtocol::do_send_message(SrsMessage* msg, SrsPacket* packet)
     // p set to current write position,
     // it's ok when payload is NULL and size is 0.
     char* p = (char*)msg->payload;
+    // to directly set the field.
+    char* pp = NULL;
     
     // always write the header event payload is empty.
     do {
@@ -871,14 +873,14 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& bh_size)
     int ret = ERROR_SUCCESS;
     
     int required_size = 1;
-    if ((ret = buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
+    if ((ret = in_buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
         if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
             srs_error("read 1bytes basic header failed. required_size=%d, ret=%d", required_size, ret);
         }
         return ret;
     }
     
-    char* p = buffer->bytes();
+    char* p = in_buffer->bytes();
     
     fmt = (*p >> 6) & 0x03;
     cid = *p & 0x3f;
@@ -891,7 +893,7 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& bh_size)
 
     if (cid == 0) {
         required_size = 2;
-        if ((ret = buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
+        if ((ret = in_buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
             if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
                 srs_error("read 2bytes basic header failed. required_size=%d, ret=%d", required_size, ret);
             }
@@ -904,7 +906,7 @@ int SrsProtocol::read_basic_header(char& fmt, int& cid, int& bh_size)
         srs_verbose("%dbytes basic header parsed. fmt=%d, cid=%d", bh_size, fmt, cid);
     } else if (cid == 1) {
         required_size = 3;
-        if ((ret = buffer->grow(skt, 3)) != ERROR_SUCCESS) {
+        if ((ret = in_buffer->grow(skt, 3)) != ERROR_SUCCESS) {
             if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
                 srs_error("read 3bytes basic header failed. required_size=%d, ret=%d", required_size, ret);
             }
@@ -997,13 +999,13 @@ int SrsProtocol::read_message_header(SrsChunkStream* chunk, char fmt, int bh_siz
     srs_verbose("calc chunk message header size. fmt=%d, mh_size=%d", fmt, mh_size);
     
     int required_size = bh_size + mh_size;
-    if ((ret = buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
+    if ((ret = in_buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
         if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
             srs_error("read %dbytes message header failed. required_size=%d, ret=%d", mh_size, required_size, ret);
         }
         return ret;
     }
-    char* p = buffer->bytes() + bh_size;
+    char* p = in_buffer->bytes() + bh_size;
     
     /**
     * parse the message header.
@@ -1107,7 +1109,7 @@ int SrsProtocol::read_message_header(SrsChunkStream* chunk, char fmt, int bh_siz
         mh_size += 4;
         required_size = bh_size + mh_size;
         srs_verbose("read header ext time. fmt=%d, ext_time=%d, mh_size=%d", fmt, chunk->extended_timestamp, mh_size);
-        if ((ret = buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
+        if ((ret = in_buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
             if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
                 srs_error("read %dbytes message header failed. required_size=%d, ret=%d", mh_size, required_size, ret);
             }
@@ -1210,7 +1212,7 @@ int SrsProtocol::read_message_payload(SrsChunkStream* chunk, int bh_size, int mh
     // empty message
     if (chunk->header.payload_length <= 0) {
         // need erase the header in buffer.
-        buffer->erase(bh_size + mh_size);
+        in_buffer->erase(bh_size + mh_size);
         
         srs_trace("get an empty RTMP "
                 "message(type=%d, size=%d, time=%"PRId64", sid=%d)", chunk->header.message_type, 
@@ -1238,14 +1240,14 @@ int SrsProtocol::read_message_payload(SrsChunkStream* chunk, int bh_size, int mh
     
     // read payload to buffer
     int required_size = bh_size + mh_size + payload_size;
-    if ((ret = buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
+    if ((ret = in_buffer->grow(skt, required_size)) != ERROR_SUCCESS) {
         if (ret != ERROR_SOCKET_TIMEOUT && !srs_is_client_gracefully_close(ret)) {
             srs_error("read payload failed. required_size=%d, ret=%d", required_size, ret);
         }
         return ret;
     }
-    memcpy(chunk->msg->payload + chunk->msg->size, buffer->bytes() + bh_size + mh_size, payload_size);
-    buffer->erase(bh_size + mh_size + payload_size);
+    memcpy(chunk->msg->payload + chunk->msg->size, in_buffer->bytes() + bh_size + mh_size, payload_size);
+    in_buffer->erase(bh_size + mh_size + payload_size);
     chunk->msg->size += payload_size;
     
     srs_verbose("chunk payload read completed. bh_size=%d, mh_size=%d, payload_size=%d", bh_size, mh_size, payload_size);
diff --git a/trunk/src/rtmp/srs_protocol_rtmp_stack.hpp b/trunk/src/rtmp/srs_protocol_rtmp_stack.hpp
index a17bc8fb6..50cc11642 100644
--- a/trunk/src/rtmp/srs_protocol_rtmp_stack.hpp
+++ b/trunk/src/rtmp/srs_protocol_rtmp_stack.hpp
@@ -97,8 +97,10 @@ private:
     };
 // peer in/out
 private:
+    /**
+    * underlayer socket object, send/recv bytes.
+    */
     ISrsProtocolReaderWriter* skt;
-    char* pp;
     /**
     * requests sent out, used to build the response.
     * key: transactionId
@@ -107,14 +109,33 @@ private:
     std::map<double, std::string> requests;
 // peer in
 private:
+    /**
+    * chunk stream to decode RTMP messages.
+    */
     std::map<int, SrsChunkStream*> chunk_streams;
-    SrsStream* decode_stream;
-    SrsBuffer* buffer;
+    /**
+    * bytes buffer cache, recv from skt, provide services for stream.
+    */
+    SrsBuffer* in_buffer;
+    /**
+    * input chunk size, default to 128, set by peer packet.
+    */
     int32_t in_chunk_size;
+    /**
+    * input ack size, when to send the acked packet.
+    */
     AckWindowSize in_ack_size;
 // peer out
 private:
+    /**
+    * output header cache.
+    * used for type0, 11bytes(or 15bytes with extended timestamp) header.
+    * or for type3, 1bytes(or 5bytes with extended timestamp) header.
+    */
     char out_header_cache[RTMP_MAX_FMT0_HEADER_SIZE];
+    /**
+    * output chunk size, default to 128, set by config.
+    */
     int32_t out_chunk_size;
 public:
     /**