diff --git a/srt/Packet.hpp b/srt/Packet.hpp
index 2118113d..bab6df0c 100644
--- a/srt/Packet.hpp
+++ b/srt/Packet.hpp
@@ -62,6 +62,8 @@ public:
     uint32_t timestamp;
     uint32_t dst_socket_id;
 
+    TimePoint get_ts; // recv or send time
+
 private:
     BufferRaw::Ptr _data;
 };
diff --git a/srt/PacketQueue.cpp b/srt/PacketQueue.cpp
index 20181262..7cf5f73d 100644
--- a/srt/PacketQueue.cpp
+++ b/srt/PacketQueue.cpp
@@ -20,16 +20,20 @@ bool PacketQueue::inputPacket(DataPacket::Ptr pkt) {
 
 std::list<DataPacket::Ptr> PacketQueue::tryGetPacket() {
     std::list<DataPacket::Ptr> re;
-    while (_pkt_map.find(_pkt_expected_seq) != _pkt_map.end()) {
-        re.push_back(_pkt_map[_pkt_expected_seq]);
-        _pkt_map.erase(_pkt_expected_seq);
+    auto it = _pkt_map.find(_pkt_expected_seq);
+    while ( it != _pkt_map.end()) {
+        re.push_back(it->second);
+        _last_pop_ts = it->second->get_ts;
+        _pkt_map.erase(it);
         _pkt_expected_seq++;
+        it = _pkt_map.find(_pkt_expected_seq);
     }
 
     while (_pkt_map.size() > _pkt_cap) {
         // force pop some packet
-        auto it = _pkt_map.begin();
+        it = _pkt_map.begin();
         re.push_back(it->second);
+        _last_pop_ts = it->second->get_ts;
         _pkt_expected_seq = it->second->packet_seq_number + 1;
         _pkt_map.erase(it);
     }
@@ -37,11 +41,12 @@ std::list<DataPacket::Ptr> PacketQueue::tryGetPacket() {
     while (timeLantency() > _pkt_lantency) {
         auto it = _pkt_map.begin();
         re.push_back(it->second);
+        _last_pop_ts = it->second->get_ts;
         _pkt_expected_seq = it->second->packet_seq_number + 1;
         _pkt_map.erase(it);
     }
 
-    return std::move(re);
+    return re;
 }
 
 
@@ -67,10 +72,12 @@ bool PacketQueue::dropForSend(uint32_t num){
     if(num <= _pkt_expected_seq){
         return false;
     }
-
+    decltype(_pkt_map.end()) it;
     for(uint32_t i =_pkt_expected_seq;i< num;++i){
-            if(_pkt_map.find(i) != _pkt_map.end()){
-                _pkt_map.erase(i);
+            it = _pkt_map.find(i);
+            if(it != _pkt_map.end()){
+                _last_pop_ts = it->second->get_ts;
+                _pkt_map.erase(it);
             }
     }
     _pkt_expected_seq = num;
@@ -84,6 +91,24 @@ DataPacket::Ptr PacketQueue::findPacketBySeq(uint32_t seq){
     }
     return nullptr;
 }
+uint32_t PacketQueue::timeLantencyFrom(TimePoint now){
+    return DurationCountMicroseconds(now - _last_pop_ts);
+}
+
+std::list<DataPacket::Ptr> PacketQueue::tryGetPacketByNow(TimePoint now){
+    std::list<DataPacket::Ptr> re;
+    auto it = _pkt_map.begin();
+    while(it !=_pkt_map.end()){
+        if(DurationCountMicroseconds(now-it->second->get_ts)>=_pkt_lantency){
+            re.push_back(it->second);
+            _pkt_expected_seq = it->second->packet_seq_number+1;
+            _last_pop_ts = it->second->get_ts;
+            _pkt_map.erase(it);
+        }
+        it++;
+    }
+    return re;
+}
 uint32_t PacketQueue::timeLantency() {
     if (_pkt_map.empty()) {
         return 0;
diff --git a/srt/PacketQueue.hpp b/srt/PacketQueue.hpp
index 2ba8467b..06036d75 100644
--- a/srt/PacketQueue.hpp
+++ b/srt/PacketQueue.hpp
@@ -21,6 +21,8 @@ public:
     bool inputPacket(DataPacket::Ptr pkt);
     std::list<DataPacket::Ptr> tryGetPacket();
     uint32_t timeLantency();
+    uint32_t timeLantencyFrom(TimePoint now);
+    std::list<DataPacket::Ptr> tryGetPacketByNow(TimePoint now);
     std::list<LostPair> getLostSeq();
 
     size_t getSize();
@@ -41,6 +43,8 @@ private:
     uint32_t _pkt_expected_seq = 0;
     uint32_t _pkt_cap;
     uint32_t _pkt_lantency;
+
+    TimePoint _last_pop_ts;
 };
 
 }
diff --git a/srt/SrtSession.cpp b/srt/SrtSession.cpp
index 978e28da..fe8cfc13 100644
--- a/srt/SrtSession.cpp
+++ b/srt/SrtSession.cpp
@@ -109,7 +109,7 @@ void SrtSession::onRecv(const Buffer::Ptr &buffer) {
     if(_transport){
         _transport->inputSockData(data,size,&_peer_addr);
     }else{
-        WarnL<< "ingore  data";
+        //WarnL<< "ingore  data";
     }
 }
 
diff --git a/srt/SrtTransport.cpp b/srt/SrtTransport.cpp
index 619c6377..4d5ac60e 100644
--- a/srt/SrtTransport.cpp
+++ b/srt/SrtTransport.cpp
@@ -201,6 +201,7 @@ void SrtTransport::handleHandshakeConclusion(HandshakePacket &pkt, struct sockad
         _recv_buf = std::make_shared<PacketQueue>(res->max_flow_window_size,_init_seq_number, delay*1e6);
         _send_buf = std::make_shared<PacketQueue>(res->max_flow_window_size,_init_seq_number, delay*1e6);
         _send_packet_seq_number = _init_seq_number;
+        _buf_delay = delay;
         onHandShakeFinished(_stream_id,addr);
     } else {
         TraceL << getIdentifier() << " CONCLUSION handle repeate ";
@@ -208,6 +209,33 @@ void SrtTransport::handleHandshakeConclusion(HandshakePacket &pkt, struct sockad
     }
     _last_ack_pkt_seq_num = _init_seq_number;
 }
+void SrtTransport::bufCheckInterval(){
+    if(isPusher()){
+        if(_recv_buf->timeLantencyFrom(_now) > (_buf_delay*1e6)){
+            auto list = _recv_buf->tryGetPacketByNow(_now);
+            for(auto data : list){
+                onSRTData(std::move(data));
+            }
+            if(!list.empty()){
+                sendACKPacket();
+                _light_ack_pkt_count = 0;
+                _ack_ticker.resetTime(_now);
+            }
+
+            auto nak_interval = (_rtt+_rtt_variance*4)/2;
+            if(nak_interval >= 20*1000){
+                 nak_interval = 20*1000;
+            }
+            if(_nak_ticker.elapsedTime(_now)>nak_interval || list.empty()){
+                auto lost = _recv_buf->getLostSeq();
+                if(!lost.empty()){
+                    sendNAKPacket(lost);
+                }
+            _nak_ticker.resetTime(_now);
+            }
+        }
+    }
+}
 void SrtTransport::handleHandshake(uint8_t *buf, int len, struct sockaddr_storage *addr){
     HandshakePacket pkt;
     assert(pkt.loadFromData(buf,len));
@@ -223,7 +251,7 @@ void SrtTransport::handleHandshake(uint8_t *buf, int len, struct sockaddr_storag
     _nak_ticker.resetTime(_now);
 }
 void SrtTransport::handleKeeplive(uint8_t *buf, int len, struct sockaddr_storage *addr){
-    TraceL;
+    //TraceL;
     sendKeepLivePacket();
 }
 
@@ -260,7 +288,7 @@ void SrtTransport::sendMsgDropReq(uint32_t first ,uint32_t last){
     sendControlPacket(pkt,true);
 }
 void SrtTransport::handleNAK(uint8_t *buf, int len, struct sockaddr_storage *addr){
-    TraceL;
+    //TraceL;
     NAKPacket pkt;
     pkt.loadFromData(buf,len);
     bool empty = false;
@@ -291,7 +319,7 @@ void SrtTransport::handleShutDown(uint8_t *buf, int len, struct sockaddr_storage
 void SrtTransport::handleDropReq(uint8_t *buf, int len, struct sockaddr_storage *addr){
     MsgDropReqPacket pkt;
     pkt.loadFromData(buf,len);
-    TraceL<<"drop "<<pkt.first_pkt_seq_num<<" last "<<pkt.last_pkt_seq_num;
+    //TraceL<<"drop "<<pkt.first_pkt_seq_num<<" last "<<pkt.last_pkt_seq_num;
     _recv_buf->dropForRecv(pkt.first_pkt_seq_num,pkt.last_pkt_seq_num);
 }
 void SrtTransport::handleUserDefinedType(uint8_t *buf, int len, struct sockaddr_storage *addr){
@@ -315,10 +343,6 @@ void SrtTransport::handlePeerError(uint8_t *buf, int len, struct sockaddr_storag
 }
 
 void SrtTransport::sendACKPacket() {
-     if(_last_ack_pkt_seq_num == _recv_buf->getExpectedSeq()){
-        return;
-    }
-
     ACKPacket::Ptr pkt=std::make_shared<ACKPacket>();
     pkt->dst_socket_id = _peer_socket_id;
     pkt->timestamp = DurationCountMicroseconds(_now - _start_timestamp);
@@ -337,9 +361,6 @@ void SrtTransport::sendACKPacket() {
     //TraceL<<"send  ack "<<pkt->dump();
 }
 void SrtTransport::sendLightACKPacket() {
-    if(_last_ack_pkt_seq_num == _recv_buf->getExpectedSeq()){
-        return;
-    }
     ACKPacket::Ptr pkt=std::make_shared<ACKPacket>();
    
     pkt->dst_socket_id = _peer_socket_id;
@@ -367,7 +388,7 @@ void SrtTransport::sendNAKPacket(std::list<PacketQueue::LostPair>& lost_list){
 
     pkt->storeToData();
 
-    TraceL<<"send NAK "<<pkt->dump();
+    //TraceL<<"send NAK "<<pkt->dump();
     sendControlPacket(pkt,true);
 }
 
@@ -381,6 +402,8 @@ void SrtTransport::sendShutDown(){
 void SrtTransport::handleDataPacket(uint8_t *buf, int len, struct sockaddr_storage *addr){
     DataPacket::Ptr pkt = std::make_shared<DataPacket>();
     pkt->loadFromData(buf,len);
+
+    pkt->get_ts = _now;
    
     //TraceL<<" seq="<< pkt->packet_seq_number<<" ts="<<pkt->timestamp<<" size="<<pkt->payloadSize()<<\
     //" PP="<<(int)pkt->PP<<" O="<<(int)pkt->O<<" kK="<<(int)pkt->KK<<" R="<<(int)pkt->R;
@@ -399,11 +422,14 @@ void SrtTransport::handleDataPacket(uint8_t *buf, int len, struct sockaddr_stora
     auto list = _recv_buf->tryGetPacket();
 
     for(auto data : list){
-        onSRTData(std::move(data),addr);
+        onSRTData(std::move(data));
     }
 
     auto nak_interval = (_rtt+_rtt_variance*4)/2;
-    if(_nak_ticker.elapsedTime(_now)>20*1000 && _nak_ticker.elapsedTime(_now)>nak_interval){
+    if(nak_interval >= 20*1000){
+        nak_interval = 20*1000;
+    }
+    if(_nak_ticker.elapsedTime(_now)>nak_interval || list.empty()){
         auto lost = _recv_buf->getLostSeq();
         if(!lost.empty()){
              sendNAKPacket(lost);
@@ -427,6 +453,8 @@ void SrtTransport::handleDataPacket(uint8_t *buf, int len, struct sockaddr_stora
         _light_ack_pkt_count = 0;
     }
     _light_ack_pkt_count++;
+
+    bufCheckInterval();
 }
 
 void SrtTransport::sendDataPacket(DataPacket::Ptr pkt,char* buf,int len, bool flush) { 
diff --git a/srt/SrtTransport.hpp b/srt/SrtTransport.hpp
index 0cf93b35..af19060e 100644
--- a/srt/SrtTransport.hpp
+++ b/srt/SrtTransport.hpp
@@ -8,6 +8,7 @@
 
 #include "Network/Session.h"
 #include "Poller/EventPoller.h"
+#include "Poller/Timer.h"
 
 #include "Common.hpp"
 #include "Packet.hpp"
@@ -45,8 +46,11 @@ public:
     void unregisterSelf();
 protected:
     virtual void onHandShakeFinished(std::string& streamid,struct sockaddr_storage *addr){};
-    virtual void onSRTData(DataPacket::Ptr pkt,struct sockaddr_storage *addr){};
+    virtual void onSRTData(DataPacket::Ptr pkt){};
     virtual void onShutdown(const SockException &ex);
+    virtual bool isPusher(){
+        return true;
+    };
 
 private:
     void registerSelfHandshake();
@@ -76,6 +80,8 @@ private:
     void sendShutDown();
     void sendMsgDropReq(uint32_t first ,uint32_t last);
 
+    void bufCheckInterval();
+
     size_t getPayloadSize();
 protected:
     void sendDataPacket(DataPacket::Ptr pkt,char* buf,int len,bool flush = false);
@@ -105,6 +111,7 @@ private:
     uint32_t _send_msg_number = 1;
 
     PacketQueue::Ptr _send_buf;
+    uint32_t _buf_delay = 120;
     PacketQueue::Ptr _recv_buf;
     uint32_t _rtt = 100*1000;
     uint32_t _rtt_variance =50*1000;
diff --git a/srt/SrtTransportImp.cpp b/srt/SrtTransportImp.cpp
index 5bae174a..b12e6e7c 100644
--- a/srt/SrtTransportImp.cpp
+++ b/srt/SrtTransportImp.cpp
@@ -48,13 +48,10 @@ void SrtTransportImp::onHandShakeFinished(std::string &streamid,struct sockaddr_
         emitOnPlay();
     }
 }
-void SrtTransportImp::onSRTData(DataPacket::Ptr pkt,struct sockaddr_storage *addr) {
+void SrtTransportImp::onSRTData(DataPacket::Ptr pkt) {
     if(!_is_pusher){
         WarnP(this)<<"this is a player data ignore";
         return;
-    }
-     if(!_addr){
-       _addr.reset(new sockaddr_storage(*((sockaddr_storage *)addr)));
     }
     if (_decoder) {
         _decoder->input(reinterpret_cast<const uint8_t *>(pkt->payloadData()), pkt->payloadSize());
diff --git a/srt/SrtTransportImp.hpp b/srt/SrtTransportImp.hpp
index 8abe2b40..36a07e01 100644
--- a/srt/SrtTransportImp.hpp
+++ b/srt/SrtTransportImp.hpp
@@ -36,7 +36,7 @@ public:
 protected:
     ///////SrtTransport override///////
     void onHandShakeFinished(std::string& streamid,struct sockaddr_storage *addr) override;
-    void onSRTData(DataPacket::Ptr pkt,struct sockaddr_storage *addr) override;
+    void onSRTData(DataPacket::Ptr pkt) override;
     void onShutdown(const SockException &ex) override;
 
     void sendPacket(Buffer::Ptr pkt,bool flush =  true) override{
@@ -44,6 +44,10 @@ protected:
         SrtTransport::sendPacket(pkt,flush);
     };
 
+    bool isPusher() override{
+        return _is_pusher;
+    }
+
     ///////MediaSourceEvent override///////
     // 关闭
     bool close(mediakit::MediaSource &sender, bool force) override;