Focuses clicked video thumbnail and prevents from switching to new large video.

app.js

  */
 var ssrc2videoType = {};
 var videoSrcToSsrc = {};
+/**
+ * Currently focused video "src"(displayed in large video).
+ * @type {String}
+ */
+var focusedVideoSrc = null;
 var mutedAudios = {};
 
 var localVideoSrc = null;
     }
 });
 
+/**
+ * Returns the JID of the user to whom given <tt>videoSrc</tt> belongs.
+ * @param videoSrc the video "src" identifier.
+ * @returns {null | String} the JID of the user to whom given <tt>videoSrc</tt>
+ *                   belongs.
+ */
+function getJidFromVideoSrc(videoSrc)
+{
+    if (videoSrc === localVideoSrc)
+        return connection.emuc.myroomjid;
+
+    var ssrc = videoSrcToSsrc[videoSrc];
+    if (!ssrc)
+    {
+        return null;
+    }
+    return ssrc2jid[ssrc];
+}
+
+/**
+ * Gets the selector of video thumbnail container for the user identified by
+ * given <tt>userJid</tt>
+ * @param userJid user's Jid for whom we want to get the video container.
+ */
+function getParticipantContainer(userJid)
+{
+    if (!userJid)
+        return null;
+
+    if (userJid === connection.emuc.myroomjid)
+        return $("#localVideoContainer");
+    else
+        return $("#participant_" + Strophe.getResourceFromJid(userJid));
+}
+
 function handleVideoThumbClicked(videoSrc) {
+    // Restore style for previously focused video
+    var oldContainer =
+        getParticipantContainer(
+            getJidFromVideoSrc(focusedVideoSrc));
+    if (oldContainer)
+        oldContainer.removeClass("videoContainerFocused");
+
+    // Unlock
+    if (focusedVideoSrc === videoSrc)
+    {
+        focusedVideoSrc = null;
+        return;
+    }
+
+    // Lock new video
+    focusedVideoSrc = videoSrc;
+
+    var userJid = getJidFromVideoSrc(videoSrc);
+    if (userJid)
+    {
+        var container = getParticipantContainer(userJid);
+        container.addClass("videoContainerFocused");
+    }
 
     $(document).trigger("video.selected", [false]);
 
         videoelem.show();
         resizeThumbnails();
 
-        updateLargeVideo(videoelem.attr('src'), 1);
+        if (!focusedVideoSrc)
+            updateLargeVideo(videoelem.attr('src'), 1);
 
         showFocusIndicator();
     }
         }
     }, 10);
 
+    // Unlock large video
+    if (focusedVideoSrc)
+    {
+        if (getJidFromVideoSrc(focusedVideoSrc) === jid)
+        {
+            console.info("Focused video owner has left the conference");
+            focusedVideoSrc = null;
+        }
+    }
+
     connection.jingle.terminateByJid(jid);
 
     if (focus == null

css/videolayout_default.css

     z-index: 3;
 }
 
+#remoteVideos .videocontainer.videoContainerFocused {
+    border: 3px solid #388396;
+}
+
 #localVideoWrapper {
     display:inline-block;
     -webkit-mask-box-image: url(../images/videomask.svg);

data_channels.js

-/* global connection, Strophe, updateLargeVideo*/
+/* global connection, Strophe, updateLargeVideo, focusedVideoSrc*/
 /**
  * Callback triggered by PeerConnection when new data channel is opened
  * on the bridge.
         console.info("Got Data Channel Message:", msgData, dataChannel);
 
         // Active speaker event
-        if (msgData.indexOf('activeSpeaker') === 0)
+        if (msgData.indexOf('activeSpeaker') === 0 && !focusedVideoSrc)
         {
             // Endpoint ID from the bridge
             var endpointId = msgData.split(":")[1];