I did a fresh install of Linux Mint 20 a few days ago and installed the Kdenlive flatpak (20.08.1) from the software manager.

When I rendered some short video clips I recorded today, everything seemed fine when it rendered them as an mp4 to my Linux Video folder. However, when I copied them over to my phone, they suddenly became unplayable and unrecognizable (the fize size remains the same though).

In my Videos folder, it plays fine. Properties show "File type: Video (video/mp4)"

After transferring to my phone, the thumbnail disappears and the file type says "Unknown (application/octet-stream)"

When I try to open it, it says "The file "(video name)" has no known programs associated with it. Use the Open With dialog to pick a program to open it with"

I tried various ways to transfer such as dropbox and google drive and they all turned out this way. Previous video files that I have rendered in the past (pre-Linux Mint 20 installation) don't have this problem.

I have used Kdenlive for a long time and never encountered this issue before.


Any ideas?

Fixed the issue. Before rendering, I would erase the "untitled.mp4" part in the path and replace it with a new name but didn't add .mp4 to the end. Adding .mp4 to the end of the name fixed it.