diff --git a/thrimbletrimmer/scripts/IO.js b/thrimbletrimmer/scripts/IO.js
index c682c69..cc69803 100644
--- a/thrimbletrimmer/scripts/IO.js
+++ b/thrimbletrimmer/scripts/IO.js
@@ -248,6 +248,9 @@ thrimbletrimmerSubmit = function(state) {
     console.log(wubData);
     console.log(JSON.stringify(wubData));
 
+	if (!wubData.video_start) {alert("No start time set"); return;}
+	if (!wubData.video_end) {alert("No end time set"); return;}
+
     //Submit to thrimshim
     var rowId = /id=(.*)(?:&|$)/.exec(document.location.search)[1];
     fetch("/thrimshim/"+rowId, {
diff --git a/thrimbletrimmer/scripts/playerSetup.js b/thrimbletrimmer/scripts/playerSetup.js
index 35776f2..75a47d1 100644
--- a/thrimbletrimmer/scripts/playerSetup.js
+++ b/thrimbletrimmer/scripts/playerSetup.js
@@ -87,6 +87,8 @@ getRealTimeForPlayerTime = function(discontinuities, playbackIndex) {
         streamStart = lastDiscontinuity.segmentTimestamp;
         playbackIndex -= lastDiscontinuity.playbackIndex;
     }
-    
-    return new Date(streamStart.getTime()+playbackIndex*1000).toISOString();
+
+	var realTime = streamStart.getTime()+playbackIndex*1000;
+
+    return (isFinite(realTime)) ? new Date(realTime).toISOString() : null;
 };