The "MP4" suffix is not arbitrary. Between 2005 and 2015, physical media dominated the Jr Idol market. Content was distributed via (using MPEG-2 codec). A single DVD held roughly 4.7GB. As portable devices (iPods, early smartphones, PSPs) became popular, fans needed to convert these DVDs.
Assuming you have legally obtained content (e.g., you ripped your own purchased DVDs), proper file management is key. Jr Idol Mp4
The "Mp4" suffix indicates a digital video file commonly used for distributing these DVD segments online. Important Context & Controversy The "MP4" suffix is not arbitrary