Files with mtv2 extension are used as a settings files in Apple Video Player.
MTV2 file extension - Apple Video Player preference file
What is mtv2 file? How to open mtv2 files?
File type specification:
The mtv2 file extension is associated with Apple Video Player, an older free video player for Macintosh computers.
Apple Video Player allows you to view and control video using your Mac in conjunction with Apple's TV/FM Radio System, Apple Video System, and Apple MPEG Media System.