You have openh264 installed already which should cover your bases. Since it quite clearly isn't I'm not sure what to suggest. What file manager is this that's having issues?
Ext4
Ext4 is a filesystem. That is the part of the kernel that actually stores and retrieves the files on disk. What program are you using to browse files? It's a bit hard to tell from this screenshot what program it's a screenshot of, but it looks like Nautilus (the default file browser in GNOME). Is that it?
You have openh264 installed already which should cover your bases. Since it quite clearly isn't I'm not sure what to suggest. What file manager is this that's having issues?
Ext4
Ext4 is a filesystem. That is the part of the kernel that actually stores and retrieves the files on disk. What program are you using to browse files? It's a bit hard to tell from this screenshot what program it's a screenshot of, but it looks like Nautilus (the default file browser in GNOME). Is that it?