I'm often trying to show an mp4 file with OpenLP but it
doesn't work. I'm using Windows 7 and so try to convert films to WMV,
which then plays through Media Player. However, this isn't always
convenient. I have VLC Player, which is great in most respects, and can
play mp4s, but Open LP won't automatically open VLC when I have an MP4
file in the service outline.