I had a similar problem a few weeks ago. The issue was that the extension (.m4v) wasn't being recognised as a format that VLC supports, so it was being played with the Webkit player which didn't know how to play it either (or played it with no sound, depending on whether it was on Windows or Linux). That's been fixed. See https://bugs.launchpad.net/openlp/+bug/1081090. At the time, the workaround was to rename the file to .avi. You do also need to make sure that VLC is the primary player, as indicated by mshields33.<br><br>[Weird. In the list of posts this is highlighted as a recent thread from December 5th, but now that I'm in the editor to post a reply, the comments are dated May 4th.]<br>