CMV format comes from the old Corel Move! software that was part of CorelDRAW until its removal in version 6.0. In case you own old versions CorelDRAW, you should be able to make .cmv files from various source materials, including graphics.
We do not know about any 3rd party software that can be used for png to cmv conversion, but edits of .cmv files can be done with the CMVParser utility.
Updated: January 4, 2024