How to convert .dif files to .mp4 format.
Converting Digital Interface Format directly to MPEG-4 Videos (.dif to .mp4 conversion) might be possible, even though your options are somewhat limited.
The DIF file type is essentially the DV (Digital Video File) format, and you can try using a video editing software or (online) conversion tool, such as Prism Video Converter or VLC Media Player, which should allow users to import DIF/DV videos and export them in MP4 format.