MP4 Play Issues

Hello,

We have been successfully playing mp4 files on our Quelea for kids class songs (lyric videos that were converted from YouTube). We have files for our main Quelea that are mp4 and are still working, but the program on this computer just stopped. It went from not playing any newly converted mp4 files to not playing any of the ones we had previously downloaded and converted. Anyone able to help me out?

Thank you

Also, things I’ve done to try to “fix” the issue in my limited knowledge: 1) uninstall and reinstall newest version of Quelea 2) uninstall converter program 3) restarted computer 4) uninstall and reinstall newest version of Quelea again.
My mp4 files are still not working - and these were the original files that were working. Thank you. This also applies to background files I had downloaded that were mp4 files, as well.

(asuming the kids computer runs Windows) If you double-click a mp4 file in the Windows Explorer: does it start playing in the VLC media player?

We have the VLC media player, but it actually opens with another program. It looks like the Movies & TV app with Microsoft. But that’s the program it was using to play these videos when you double clicked on it beforehand, as well.

If you right-click a mp4 in the Explorer and choose open with VLC media player: does it start playing in the VLC media player? (if not: uninstall and reinstall VLC)