diff --git a/WebRTC-Sample-App/Base.lproj/Main.storyboard b/WebRTC-Sample-App/Base.lproj/Main.storyboard
index 9796ef7..f9a820e 100644
--- a/WebRTC-Sample-App/Base.lproj/Main.storyboard
+++ b/WebRTC-Sample-App/Base.lproj/Main.storyboard
@@ -172,9 +172,8 @@ WebRTC Live Streaming</string>
                         <rect key="frame" x="0.0" y="0.0" width="390" height="834"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
-                            <collectionView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" fixedFrame="YES" dataMode="prototypes" translatesAutoresizingMaskIntoConstraints="NO" id="v8Q-eO-C1v">
-                                <rect key="frame" x="0.0" y="0.0" width="390" height="834"/>
-                                <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                            <collectionView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" dataMode="prototypes" translatesAutoresizingMaskIntoConstraints="NO" id="v8Q-eO-C1v">
+                                <rect key="frame" x="0.0" y="200" width="390" height="634"/>
                                 <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                 <collectionViewFlowLayout key="collectionViewLayout" automaticEstimatedItemSize="YES" minimumLineSpacing="10" minimumInteritemSpacing="10" id="2Nz-ci-6za">
                                     <size key="itemSize" width="272" height="256"/>
@@ -217,17 +216,32 @@ WebRTC Live Streaming</string>
                                     <constraint firstAttribute="width" constant="90" id="tMd-w9-0ro"/>
                                 </constraints>
                             </view>
+                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="9Y7-Gu-YHc" customClass="RTCMTLVideoView">
+                                <rect key="frame" x="0.0" y="0.0" width="390" height="200"/>
+                                <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                                <constraints>
+                                    <constraint firstAttribute="height" constant="200" id="nbV-00-tZd"/>
+                                </constraints>
+                            </view>
                         </subviews>
                         <viewLayoutGuide key="safeArea" id="dqn-Tz-Jj5"/>
                         <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                         <constraints>
                             <constraint firstItem="dqn-Tz-Jj5" firstAttribute="bottom" secondItem="Zwp-DO-5T7" secondAttribute="bottom" constant="20" id="Fpc-aE-wjW" userLabel="Safe Area.bottom = Local View.bottom"/>
+                            <constraint firstItem="9Y7-Gu-YHc" firstAttribute="top" secondItem="dqn-Tz-Jj5" secondAttribute="top" id="GSq-UA-gQi"/>
+                            <constraint firstItem="dqn-Tz-Jj5" firstAttribute="trailing" secondItem="v8Q-eO-C1v" secondAttribute="trailing" id="HDn-DF-pPN"/>
+                            <constraint firstItem="9Y7-Gu-YHc" firstAttribute="leading" secondItem="dqn-Tz-Jj5" secondAttribute="leading" id="Moc-Ar-up1"/>
+                            <constraint firstItem="v8Q-eO-C1v" firstAttribute="leading" secondItem="dqn-Tz-Jj5" secondAttribute="leading" id="O2j-tb-89J"/>
+                            <constraint firstItem="v8Q-eO-C1v" firstAttribute="bottom" secondItem="dqn-Tz-Jj5" secondAttribute="bottom" id="Rlb-vc-OLv"/>
+                            <constraint firstItem="v8Q-eO-C1v" firstAttribute="top" secondItem="9Y7-Gu-YHc" secondAttribute="bottom" id="ZD8-86-4wP"/>
                             <constraint firstItem="dqn-Tz-Jj5" firstAttribute="trailing" secondItem="Zwp-DO-5T7" secondAttribute="trailing" constant="33" id="pND-Zi-qjI" userLabel="Safe Area.trailing = Local View.trailing"/>
+                            <constraint firstItem="9Y7-Gu-YHc" firstAttribute="trailing" secondItem="dqn-Tz-Jj5" secondAttribute="trailing" id="zg8-Rt-pHw"/>
                         </constraints>
                     </view>
                     <navigationItem key="navigationItem" id="l7b-W5-MXv"/>
                     <connections>
                         <outlet property="collectionView" destination="v8Q-eO-C1v" id="tlK-Cg-lCn"/>
+                        <outlet property="heroView" destination="9Y7-Gu-YHc" id="D6o-t3-s6g"/>
                         <outlet property="localView" destination="Zwp-DO-5T7" id="ada-FF-Y7z"/>
                     </connections>
                 </viewController>
diff --git a/WebRTC-Sample-App/ConferenceViewController.swift b/WebRTC-Sample-App/ConferenceViewController.swift
index 0de2383..50b0864 100644
--- a/WebRTC-Sample-App/ConferenceViewController.swift
+++ b/WebRTC-Sample-App/ConferenceViewController.swift
@@ -20,16 +20,24 @@ open class ConferenceViewController: UIViewController ,  AVCaptureVideoDataOutpu
     var clientUrl: String!
     var roomId: String!
     var publisherStreamId: String!
-    
+        
     @IBOutlet var localView: UIView!
         
     @IBOutlet weak var collectionView: UICollectionView!
     
+    @IBOutlet weak var heroView: RTCMTLVideoView!
     //keeps which remoteView renders which track according to the index
     var remoteViewTrackMap: [RTCVideoTrack?] = [];
+    
+    var heroVideoTrack: RTCVideoTrack?;
         
     var conferenceClient: AntMediaClient?;
     
+    //key is the videoTrack in WebRTC
+    //value is the streamId in the server
+    var videoTrackMap: [String: String] = [:]
+
+    
     func generateRandomAlphanumericString(length: Int) -> String {
         let characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
         return String((0..<length).map{ _ in characters.randomElement()! })
@@ -84,7 +92,7 @@ open class ConferenceViewController: UIViewController ,  AVCaptureVideoDataOutpu
 extension ConferenceViewController: AntMediaClientDelegate
 {
     public func clientHasError(_ message: String) {
-        
+        debugPrint("Error is \(message)");
     }
     
     public func dataReceivedFromDataChannel(streamId: String, data: Data, binary: Bool) {
@@ -177,6 +185,8 @@ extension ConferenceViewController: AntMediaClientDelegate
                     {
                         
                         print("videoLabel:\(videoLabel) plays the trackId:\(trackId)")
+                        
+                        videoTrackMap["ARDAMSv" + videoLabel] = trackId;
                         //On the server side, we create WebRTC tracks with ARDAMSv{VIDEO_LABEL}
                         //It's useful in limiting/dynamic allocation of the streams and tracks in a conference call
                         //If you want to make sure, which webrtc track is playing which real streamId,
@@ -189,6 +199,9 @@ extension ConferenceViewController: AntMediaClientDelegate
                 }
             }
         }
+        else if (eventType == RESOLUTION_CHANGE_INFO_COMMAND) {
+            AntMediaClient.printf("Resolution has changed");
+        }
     }
 }
 
@@ -206,6 +219,40 @@ extension ConferenceViewController: UICollectionViewDataSource {
         return cell
     }
     
+    
+    public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
+        debugPrint("Item selected at \(indexPath.item)")
+        if let videoTrack = heroVideoTrack {
+            //if there is already heroVideoTrack, remove from renderer
+            videoTrack.remove(heroView);
+            //add to the current grid
+            remoteViewTrackMap.append(videoTrack)
+            
+            //decrease the quality
+            if let videoTrackId = videoTrackMap[videoTrack.trackId] {
+                conferenceClient?.forceStreamQuality(resolutionHeight: 240, streamId:  videoTrackId )
+            }
+           
+        }
+        
+        //get new track
+        heroVideoTrack = remoteViewTrackMap.remove(at: indexPath.item)
+        //render it in hero view
+        heroVideoTrack?.add(heroView);
+        //increase the resolution to 720
+        if let videoTrack = heroVideoTrack
+        {
+            if let videoTrackId = videoTrackMap[videoTrack.trackId] {
+                conferenceClient?.forceStreamQuality(resolutionHeight: 720, streamId: videoTrackId);
+            }
+        }
+        
+        //update the grid
+        collectionView.reloadData()
+        
+        
+    }
+    
 }
 
 extension ConferenceViewController: UICollectionViewDelegateFlowLayout {