diff --git a/client/webrtc_demo/src/mainwindow.cpp b/client/webrtc_demo/src/mainwindow.cpp
index 18e25b6..c3ee93e 100644
--- a/client/webrtc_demo/src/mainwindow.cpp
+++ b/client/webrtc_demo/src/mainwindow.cpp
@@ -8,6 +8,9 @@
 #include <Lmcons.h>
 #include <QAction>
 
+const char kCandidateSdpMidName[] = "sdpMid";
+const char kCandidateSdpMlineIndexName[] = "sdpMLineIndex";
+const char kCandidateSdpName[] = "candidate";
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
@@ -55,6 +58,11 @@ const char kAudioLabel[] = "audio_label";
 const char kVideoLabel[] = "video_label";
 const char kStreamId[] = "stream_id";
 
+void WebrtcHanlder::SetRemotePeerName(QString remote)
+{
+    this->mRemoteName = remote;
+}
+
 int WebrtcHanlder::InitWebrtc()
 {
     m_peer_connection_factory_ = webrtc::CreatePeerConnectionFactory(
@@ -100,8 +108,7 @@ int WebrtcHanlder::InitWebrtc()
         qDebug() << "Failed to add audio track to PeerConnection: "
                         << result_or_error.error().message();
     }
-    //rtc::scoped_refptr<CapturerTrackSource> video_device =
-    //    CapturerTrackSource::Create();
+
     rtc::scoped_refptr<MyCapturer> video_device = new rtc::RefCountedObject<MyCapturer>();
     if (video_device) {
         video_device->startCapturer();
@@ -154,7 +161,6 @@ int WebrtcHanlder::AddTrack()
         RTC_LOG(LS_ERROR) << "OpenVideoCaptureDevice failed";
     }
 
-    webrtc::DataChannelInit config;
 
 }
 
@@ -165,6 +171,7 @@ void WebrtcHanlder::SetSignalClient(SignalClient * cli)
 
 void WebrtcHanlder::CreateOffer()
 {
+    qDebug()<<"CreateOffer";
     if(nullptr != m_peer_connection_){
         m_peer_connection_->CreateOffer(this,
             webrtc::PeerConnectionInterface::RTCOfferAnswerOptions());
@@ -190,10 +197,18 @@ void WebrtcHanlder::SetRemoteSdp(QString sdp)
     qDebug()<<"recv" << sdp;
     auto doc  = QJsonDocument::fromJson(sdp.toUtf8());
     auto obj = doc.object();
-
+    auto ssdp = obj["sdp"].toString();
+    auto type = obj["type"].toString();
+    webrtc::SdpType ktype;
     webrtc::SdpParseError error;
+    if(type == "answer"){
+        ktype = webrtc::SdpType::kAnswer;
+    }
+    if(type == "offer"){
+        ktype = webrtc::SdpType::kOffer;
+    }
     std::unique_ptr<webrtc::SessionDescriptionInterface> session_description =
-        webrtc::CreateSessionDescription(webrtc::SdpType::kOffer, sdp.toStdString(), &error);
+        webrtc::CreateSessionDescription(ktype, ssdp.toStdString(), &error);
 
     if (!session_description) {
         RTC_LOG(WARNING) << "Can't parse received session description message. "
@@ -210,8 +225,31 @@ void WebrtcHanlder::SetRemoteSdp(QString sdp)
 
 }
 
+void WebrtcHanlder::SetRemoteCandidate(QString scandidate)
+{
+    qDebug()<<scandidate;
+
+    auto doc  = QJsonDocument::fromJson(scandidate.toUtf8());
+    auto obj = doc.object();
+    auto ssdp = obj["candidate"].toString();
+    std::string sdp_mid,sdps;
+    int sdp_mlineindex = 0;
+
+    sdp_mlineindex = obj[kCandidateSdpMlineIndexName].toInt();
+    sdp_mid = obj[kCandidateSdpMlineIndexName].toString().toStdString();
+    sdps = obj[kCandidateSdpName].toString().toStdString();
+    webrtc::SdpParseError error;
+    std::unique_ptr<webrtc::IceCandidateInterface> candidate(
+        webrtc::CreateIceCandidate(sdp_mid, sdp_mlineindex, sdps, &error));
+
+    if(nullptr != m_peer_connection_){
+        m_peer_connection_->AddIceCandidate(candidate.get());
+    }
+}
+
 void WebrtcHanlder::CreateAnwer()
 {
+    qDebug()<<"create answer";
     m_peer_connection_->CreateAnswer(
         this, webrtc::PeerConnectionInterface::RTCOfferAnswerOptions());
 }
@@ -225,18 +263,20 @@ void WebrtcHanlder::OnSignalingChange(webrtc::PeerConnectionInterface::Signaling
 
 }
 
-void WebrtcHanlder::OnAddTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver, const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface> > &streams)
+void WebrtcHanlder::OnAddTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
+                               const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface> > &streams)
 {
-
+    qDebug()<<"OnAddTrack";
+    RTC_LOG(INFO) << __FUNCTION__ << " " << receiver->id();
 }
 
 void WebrtcHanlder::OnRemoveTrack(rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver)
 {
-
+    qDebug()<<"OnRemoveTrack";
 }
 
 void WebrtcHanlder::OnDataChannel(rtc::scoped_refptr<webrtc::DataChannelInterface> channel) {
-
+    qDebug()<<"OnRemoveTrack";
 }
 
 void WebrtcHanlder::OnIceConnectionChange(webrtc::PeerConnectionInterface::IceConnectionState new_state) {
@@ -246,14 +286,9 @@ void WebrtcHanlder::OnIceConnectionChange(webrtc::PeerConnectionInterface::IceCo
 void WebrtcHanlder::OnIceGatheringChange(webrtc::PeerConnectionInterface::IceGatheringState new_state) {
 
 }
-const char kCandidateSdpMidName[] = "sdpMid";
-const char kCandidateSdpMlineIndexName[] = "sdpMLineIndex";
-const char kCandidateSdpName[] = "candidate";
 
 void WebrtcHanlder::OnIceCandidate(const webrtc::IceCandidateInterface *candidate)
 {
-    qDebug()<<"on condidate\r\n";
-
     QJsonObject addr;
     addr.insert(kCandidateSdpMidName, candidate->sdp_mid().c_str());
     addr.insert(kCandidateSdpMlineIndexName,candidate->sdp_mline_index());
@@ -263,7 +298,8 @@ void WebrtcHanlder::OnIceCandidate(const webrtc::IceCandidateInterface *candidat
       return;
     }
     addr.insert(kCandidateSdpName,sdp.c_str());
-    qDebug()<<"condidate:\r\n"<< QString(QJsonDocument(addr).toJson());
+    qDebug()<<"OnIceCandidate:\r\n"<< QString(QJsonDocument(addr).toJson());
+    this->mClient->SendICECandidate(mRemoteName,QString(QJsonDocument(addr).toJson()));
 }
 
 void WebrtcHanlder::OnIceConnectionReceivingChange(bool receiving) {
@@ -333,22 +369,41 @@ void MainWindow::signal_response(int type,QJsonObject data)
     qDebug()<<type<<data;
     switch (type) {
     case 2004:
-        this->mModel->clear();
-        for (auto itr = data.begin();itr != data.end();itr++){
-            auto item = new QStandardItem(itr.key());
-            item->setEditable(false);
-            mModel->appendRow(item);
+        {
+            qDebug()<<"2004";
+            this->mModel->clear();
+            for (auto itr = data.begin();itr != data.end();itr++){
+                auto item = new QStandardItem(itr.key());
+                item->setEditable(false);
+                mModel->appendRow(item);
+            }
+            break;
         }
-        break;
-    case 2005:
-        auto sdp = data["sdp"].toString();
-        auto remote_name = data["remote_name"].toString();
+        case 2005:
+        {
+            qDebug()<<"2005";
+            auto sdp = data["sdp"].toString();
+            auto remote_name = data["remote_name"].toString();
+            mHandler->SetRemotePeerName(remote_name);
 
-        this->mHandler.get()->SetRemoteSdp(sdp);
-        mRemoteName = remote_name;
-        if(!mCalling)
-            mHandler->CreateAnwer();
-        break;
+            this->mHandler.get()->SetRemoteSdp(sdp);
+            mRemoteName = remote_name;
+            if(!mCalling)
+                mHandler->CreateAnwer();
+            break;
+        }
+    case 2006:
+        {
+            qDebug()<<"2006";
+            auto candidate = data["candidate"].toString();
+            auto remote_names = data["remote_name"].toString();
+            mHandler->SetRemotePeerName(remote_names);
+            this->mHandler.get()->SetRemoteCandidate(candidate);
+            mRemoteName = remote_names;
+            qDebug()<<"recv candidate"<<candidate;
+
+            break;
+        }
     }
 }
 
@@ -361,6 +416,7 @@ void MainWindow::itemClicked(QModelIndex index)
     //mSignalClient->SendSDPOffer();
     qDebug()<<mModel->item(index.row())->text();
     mRemoteName = mModel->item(index.row())->text();
+    mHandler->SetRemotePeerName(mRemoteName);
     mCalling = true;
 
 }
diff --git a/client/webrtc_demo/src/mainwindow.h b/client/webrtc_demo/src/mainwindow.h
index 4ce576c..5d94359 100644
--- a/client/webrtc_demo/src/mainwindow.h
+++ b/client/webrtc_demo/src/mainwindow.h
@@ -35,20 +35,69 @@ namespace Ui { class MainWindow; }
 QT_END_NAMESPACE
 
 
+class VideoRenderer : public rtc::VideoSinkInterface<webrtc::VideoFrame> {
+
+ public:
+  VideoRenderer(HWND wnd,
+                int width,
+                int height,
+                webrtc::VideoTrackInterface* track_to_render);
+  virtual ~VideoRenderer();
+
+  void Lock() { ::EnterCriticalSection(&buffer_lock_); }
+
+  void Unlock() { ::LeaveCriticalSection(&buffer_lock_); }
+
+  // VideoSinkInterface implementation
+  void OnFrame(const webrtc::VideoFrame& frame) override;
+
+  const BITMAPINFO& bmi() const { return bmi_; }
+  const uint8_t* image() const { return image_.get(); }
+
+ protected:
+  void SetSize(int width, int height);
+
+  enum {
+    SET_SIZE,
+    RENDER_FRAME,
+  };
+
+  HWND wnd_;
+  BITMAPINFO bmi_;
+  std::unique_ptr<uint8_t[]> image_;
+  CRITICAL_SECTION buffer_lock_;
+  rtc::scoped_refptr<webrtc::VideoTrackInterface> rendered_track_;
+};
+
+// A little helper class to make sure we always to proper locking and
+// unlocking when working with VideoRenderer buffers.
+template <typename T>
+class AutoLock {
+ public:
+  explicit AutoLock(T* obj) : obj_(obj) { obj_->Lock(); }
+  ~AutoLock() { obj_->Unlock(); }
+
+ protected:
+  T* obj_;
+};
+
+
 class WebrtcHanlder :public QObject,
         public webrtc::PeerConnectionObserver,
         public webrtc::CreateSessionDescriptionObserver{
     Q_OBJECT
-
 signals:
     void OnOfferSdp(QString);
     void OnAnswerSdp(QString);
 public:
+    void SetRemotePeerName(QString);
     int InitWebrtc();
     int AddTrack();
     void SetSignalClient(SignalClient *);
     void CreateOffer();
     void SetRemoteSdp(QString);
+    void SetRemoteCandidate(QString);
+
     void CreateAnwer();
 protected:
     ~WebrtcHanlder();
@@ -80,6 +129,7 @@ private:
     rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface>
         m_peer_connection_factory_;
     SignalClient *mClient;
+    QString mRemoteName;
 
 };
 
diff --git a/client/webrtc_demo/src/signal_client.cpp b/client/webrtc_demo/src/signal_client.cpp
index df2695a..814800b 100644
--- a/client/webrtc_demo/src/signal_client.cpp
+++ b/client/webrtc_demo/src/signal_client.cpp
@@ -91,6 +91,19 @@ void SignalClient::SendSDPOffer(QString peer, QString sdp)
 
     qDebug()<<QString(QJsonDocument(obj).toJson());
 }
+#define REQ_CANDIDATE 1006
+void SignalClient::SendICECandidate(QString peer, QString candidate)
+{
+    QJsonObject obj;
+    QJsonObject data;
+    data.insert("candidate",candidate);
+    data.insert("name",m_peer_name);
+    data.insert("remote_name",peer);
+    obj.insert("type",REQ_CANDIDATE);
+    obj.insert("data",data);
+    qDebug()<<QString(QJsonDocument(obj).toJson());
+    m_webSocket.sendTextMessage(QString(QJsonDocument(obj).toJson()));
+}
 
 QString SignalClient::PeerName()
 {
diff --git a/client/webrtc_demo/src/signal_client.h b/client/webrtc_demo/src/signal_client.h
index 69e1c39..22c4950 100644
--- a/client/webrtc_demo/src/signal_client.h
+++ b/client/webrtc_demo/src/signal_client.h
@@ -26,6 +26,8 @@ public:
     bool Connected();
     void SetURL(QString);
     void SendSDPOffer(QString peer,QString sdp);
+    void SendICECandidate(QString peer,QString sdp);
+
     QString PeerName();
 private Q_SLOTS:
     void onConnected();