Crash when playing a custom made menu_background file

One of the cool features that worked before currently doesn't work in the latest openmw version.

A custom menu_background file can play by renaming the extension to .bik and it would play properly.

Made a quick test and version 0.45 stable is the last version that does not crash.

Any valid file can be used to test, but this is what I used, the file is a .mp4. menu_background.bik

There is a crash dump but the size exceeds GitLab's upload size limit.