Fix bug where video stream continued fetching on player close.

ui-src/index.js

@@ -127,7 +127,12 @@ function onSelectVideo(camera, range, recording) {
   dialog.dialog({
       title: camera.shortName + ", " + formattedStart + " to " + formattedEnd,
       width: recording.videoSampleEntryWidth / 4,
-      close: function() { dialog.remove(); },
+      close: () => {
+        const videoDOMElement = video[0];
+        videoDOMElement.pause();
+        videoDOMElement.src = ''; // Remove current source to stop loading
+        dialog.remove();
+      },
   });
   video.attr("src", url);
 }