There is only one file type that uses the .M1PG extension:
iFinish Video Clip
Video file created with Media 100 iFinish, a professional video cutting and editing program; saved in a proprietary format that can only be opened by Media 100 software.
The iFinish program is no longer developed and has been replaced by Media 100 Producer, which is only available for Mac OS X.
Updated: January 23, 2008