Enables shared video for all participants, the first to share is the video all will see, later attempts will result just a dialog informing that video is already shared.

conference.js

         room.addCommandListener(
             Commands.SHARED_VIDEO, ({value, attributes}, id) => {
 
-                // if we are not the moderator or
-                // the command is coming from a user which is not the moderator
-                if (!(this.isLocalId(id) && room.isModerator())
-                    && !this.isParticipantModerator(id))
-                {
-                    console.warn('Received shared video command ' +
-                        'not from moderator');
-                    return;
-                }
-
                 if (attributes.state === 'stop') {
                     APP.UI.stopSharedVideo(id, attributes);
                 } else if (attributes.state === 'start') {

lang/main.json

         "shareVideoLinkError": "Please provide a correct youtube link.",
         "removeSharedVideoTitle": "Remove shared video",
         "removeSharedVideoMsg": "Are you sure you would like to remove your shared video?",
+        "alreadySharedVideoMsg": "Another participant is already sharing video. This conference allows only one shared video at a time.",
         "WaitingForHost": "Waiting for the host ...",
         "WaitForHostMsg": "The conference <b>__room__ </b> has not yet started. If you are the host then please authenticate. Otherwise, please wait for the host to arrive.",
         "IamHost": "I am the host",

modules/UI/shared_video/SharedVideo.js

             return;
         }
 
-        showStopVideoPropmpt().then(() =>
-            this.emitter.emit(UIEvents.UPDATE_SHARED_VIDEO, null, 'stop'));
+        if(APP.conference.isLocalId(this.from)) {
+            showStopVideoPropmpt().then(() =>
+                this.emitter.emit(UIEvents.UPDATE_SHARED_VIDEO, null, 'stop'));
+        } else {
+            messageHandler.openMessageDialog(
+                "dialog.shareVideoTitle",
+                "dialog.alreadySharedVideoMsg"
+            );
+        }
     }
 
     /**

modules/UI/toolbars/Toolbar.js

     },
 
     // Shows or hides the 'shared video' button.
-    showSharedVideoButton (show) {
-        if (UIUtil.isButtonEnabled('sharedvideo') && show) {
+    showSharedVideoButton () {
+        if (UIUtil.isButtonEnabled('sharedvideo')
+                && config.disableThirdPartyRequests !== true) {
             $('#toolbar_button_sharedvideo').css({display: "inline-block"});
         } else {
             $('#toolbar_button_sharedvideo').css({display: "none"});