mepj to mov conversion is typically searched by users looking for a way to export projects from Movavi Video Editor to a standard video format, for example QuickTime Movie. This is only doable with the proper version of Movavi VE and only if you have all the original multimedia data referenced in the projects, without these it won't be possible to do any kind of export. So if someone send you .mepj file, it's pretty much useless on its own.
Updated: July 24, 2023